A Father's Mission

/ Source: Dateline NBC

A father's anguish ...

Paul Crotts: Gut wrenchin. Tears your heart out. Just it's, it's just incomparable. I wouldn't wish it on my worst enemy.

Anger at the people he says stole his son's youth. Anger at himself for helping them

Paul Crotts: I slapped myself in the face with my fist. I was so bitter at myself for what I had done.

And so, his relentless quest: What really happened in this lonely farmhouse nearly twenty years ago....

David Ross: I've never been around anybody like it. I mean he's really. He's obsessed with it.

Perhaps because of the secret Paul Crotts has harbored himself all these years- has kept even from his son. Especially from his son.

Keith Morrison: Are you worried about how he'll look at you if you tell him?

Paul Crotts: Yeah.

Keith Morrison: Do you need to tell him?

Paul Crotts: Yeah.

Tucked into the corner of this town square in Graham, N.C., is a mom and pop furniture store. It's been here for sixty years - something to depend on in an uncertain world of shuttered textile plants and dilapidated farms. A place to buy a discount couch and chat about the good old days.

Paul Crotts: They'll say, Paul, I remember this little baby that used to be in the bassinet in this part of the store. And they say, who was that baby? It was me.

About everybody in town knows Paul Crotts and not just from watching him grow up in the store his daddy founded.

Paul was a high school football hero. Volunteer fireman. Champion bodybuilder. Paul tried to make his father proud. Which is why the experience with his own son was so hard for him to bear.

Keith Morrison: At the time it was like, where did that kid come from?

Paul Crotts: Oh, yeah.

Keith Morrison: He's not like me at all.

Paul Crotts: Yeah.

Did Paul ever really know his son?

Paul Crotts: The daddy is always the black sheep of the divorce.

Paul's marriage collapsed in the late 1970s. His 10-year-old son, Mark took it hard.

Linda: It was a very difficult time. Cried a lot. Couldn't understand why Daddy wasn't coming home.

Linda is Mark's mother.  She set up house a few miles, but a world away from the furniture store.  Wrong side of the tracks, maybe, but Mark thrived.  He loved the country, loved tracking deer, loved cat-fishing in the ponds. It was freedom to him.

But he dreaded weekend visits with his workaholic dad.

Linda: He was too rough with him when he disciplined him. It scared Mark. Mark, I think, was really afraid of his father.

By the time Mark was in his teens, the visits to town stopped. Mark gravitated to friends and  - just like his dad before him - became a high school football star.

But something happened in the 11th grade.  And Paul heard about it.  Mark was drinking, smoking marijuana...acting out. Mark's mother did what she could.  She put him in rehab, helped the 19-year-old set up a taxidermy business in an old barn she rented off the highway. He was good at that.

But he couldn't stop partying. At her wit's end, Mark's mother threw him out of the house/

Paul Crotts: He was penniless, living out of his car.

That's when Paul stepped back into his son's life. Became his partner in that little business...told his son to shape up...thought it was working, until he started getting those phone calls.

Paul Crotts: You need to be aware that Mark is a laughing joke out here, and people are saying that you can go steal anything from him.

Keith Morrison: Was the business making any money?

Paul Crotts: The beginning, yes. The end, no.

To Paul, it looked like Mark was spending the profits, raising Cain at the barn with his drinking buddies. People like his high school sweetheart, Kristen Vincent.

Kristen Vincent: Music really really loud. Really hard heavy metal. And there was alcohol everywhere. I remember several mentions from different people that they had taken acid.

It was behavior Mark's dad just didn't understand. He started dropping by after hours, checking on the inventory with a flashlight in the dark. Then in May 1989, just three months after he had helped his son start over, Paul says he found something unforgivable.

Paul Crotts: As I was exiting the building, I saw the marijuana in a pot. It was about three stalks.  And-- that just infuriated me.  I said, here he is, growing marijuana.  Here he is, an establishment, business, he's growing marijuana.

They say you never really know the moment when you cast the dye in your life.  Not till later.

That was Paul's moment. His choice.

Paul Crotts: I can still see the phone booth I made it from.

He called the sheriff's department and turned in his son. Tough love, he thought.

Paul Crotts: I thought maybe I could use scare tactic.

Keith Morrison: Scare him straight, as they say?

Paul Crotts: (nods)

Keith Morrison: Did you think then you'd done the right thing?

Paul Crotts: Yes, I did. 

Mark pleaded guilty to misdemeanor marijuana possession and was put on probation. He never knew it was his father who had turned him in.

And Paul wasn't done - he shut down the taxidermy business and brought his 21-year old son back to town, where he could keep an eye on him, at the furniture store. He didn't like what he saw.

Paul Crotts: I found a bag of marijuana under the seat of his truck. I confronted him. We went out back of the store, and we got in a fistfight.

Paul says he beat Mark more than once - his son pleading with him to stop. And Mark, whenever he could, sneaked away with his friends to the old taxidermy shop.

Keith Morrison: What was this thing that worried you the most about Mark in those days?

Paul Crotts: Findin' him dead or drivin' and hurtin' somebody else, an innocent.

Of course, Paul could not have known - who could? - that two innocents were about to die, steps from Mark's rented barn.  That party barn.

Paul would be faced with the ultimate choice - to cast out the son he no longer recognized, the son he could not change, or stand behind him when so few others would.

Paul Crotts: I always said if you play with fire long enough you gonna get burnt. And Mark was playing with the red hot coals.

It was a cold, crisp Saturday morning.  Thanksgiving weekend, 1990. Paul Crotts went to his furniture store, as usual. Mark Crotts tracked white tail deer in the woods. On a nearby farmhouse porch, a woman sat crying.

She'd just found the bodies of her parents.  Stabbed to death. Patrol officer Tim Smith raced toward the crime scene in his squad car.

Tim Smith: It didn’t quite make sense. Because the people were really nice. I actually knew the people.

79-year old Bill Gilliam, a retired tobacco farmer and his wife Alma - they were churchgoers, no harm to anyone. Now here they were dead in their den. Bill Gilliam was sitting in his recliner, leg up. Alma was at his feet. She'd been stabbed in the back.

Tim Smith: There's no sign of struggle. It has to be somebody they know.

Keith Morrison: How'd you find out your son had been questioned?

Paul Crotts: Phone calls from out in that area. Told me that they were questionin' Mark.

And of course Mark was an obvious suspect - that barn he rented?  It belonged to the Gilliams. Sat right across the street from their farmhouse. And there was no love lost between Mark and his landlord.

Court records showed Bill Gilliam had tried to evict Mark seven months before. And one friend told police he had seen Mark yelling threats from the road. Mark had also been spotted near the crime scene by the owner of a local convenience store.

Tim Smith: She tells me she had seen Mark in the store the night of the murders with a knife saying he's going to find something to use the knife on.

The night after the Gilliams' bodies were found, two detectives staked out Mark at a carwash. They searched his truck and asked a lot of questions. Paul didn't know what to think.

If the cops were talking to his son, surely they must know something. Paul trusted the police. Always had.  In fact, when Mark's girlfriend accused him of beating her up one time, she says Paul encouraged her to go to the cops.

Kristen Vincent: He just said I will meet you at the sheriff's department, and we will get him taken care of.

So now?

Paul Crotts: I kept digging at him, diggin’ at him, diggin’ at him, saying, Mark, do you know anything? What have you heard? Tell me something.

Paul says detectives were dropping by at the furniture store out of the blue, taking him to a nearby park, looking for leads.  Did Paul suspect his son?  Maybe he did, a little. He tried to be helpful.

Paul Crotts: They were throwing the fish line to me to see if I was gonna take the hook.

Keith Morrison: Did you ever?

Paul Crotts: Oh, yeah.

Keith Morrison: You took the hook?

Paul Crotts: Oh, yeah.

Keith Morrison: You said you thought your son might have been involved

Paul Crotts: Yeah. They asked me, did I think Mark was capable of killing and   -and this haunts me too, Keith- is I said, I think anybody is capable of killing if they're pushed so far.

If his son was capable of the boozing and the drugs, what else might he do? But Mark told his Dad again and again - he didn't know anything. And the weeks passed. Paul was now worried about something else: his son's mental health.

Paul Crotts: You'd see Mark talking to hisself. He was just not acting like the normal.

The day after Christmas, 1990, Paul approached the law about his son yet again - said he was making "homicidal threats".  Was Paul now afraid of his son? Scared of what he might do? Paul had Mark committed - against his will - to a mental institution for tests. At the hospital, doctors diagnosed a serious mental illness, prescribed ongoing medication, kept him there 5 weeks and then sent him home.

And that's when Paul began to understand how wrong he'd been about his son.  He wasn't a bad person a potential killer, he just needed help; his drug use a desperate effort to self-medicate, to fight despair.  So then, maybe for the very first time, Paul looked at Mark and saw a fellow human being, suffering.

Paul Crotts: I knew that I'd done so much wrong in this investigation to-- to throw the focus on mark.  And I kept telling myself that they'll forget about me telling that Mark or anybody's capable of killing, or Mark was drinking. Or Mark was doing marijuana.

But they didn't forget. And now it was too late. Paul watched in horror as investigators closed in yet again.

Reporter Charles Jacobs.

Charles Jacobs: They found a knife with a broken tip rusted and filthy dirty in a garbage heap out in the back of a former home where mark had lived.

Even though lab reports showed there was no "blood" on the knife, Paul says detectives told him this was the murder weapon. The missing piece of the puzzle.

Paul Crotts: And I said, "How do you know that?" And they said, "Well, we have reasons to know.  We have-- ways of knowin'." 

On Aug. 5, 1991, Mark Crotts was arrested for the capital murders of Bill and Alma Gilliam.

And Paul couldn't shake the feeling that his secret phone call, turning in his son for marijuana possession, could cost his son his life. His mind raced. Reeling.

Paul Crotts: Mark didn't kill them. What canIi do to help him?

Good question. Even now. Even now.

Paul Crotts: If that courthouse ever caught on fire, as long as there wasn't anybody in there, I would go over and blow to help burn it to the ground.

The Alamance County courthouse towers over Paul Crotts' furniture store. For seven weeks in September 1992, that's where his son was on trial for capital murder.

The prosecutors' case was simple - the murders amounted to an act of vengeance. Mark Crotts had killed farmer Gilliam and his wife because they had shopped him to the cops for marijuana possession  (or so he believed). The evidence against him? He was seen the night of the crime in the area of the Gilliam's home. And there was that knife. The knife police claimed was the murder weapon and said they had found buried in the backyard of one of Mark Crott's former homes.

It was a weak case according to Mark's defense attorneys - there was no physical evidence connecting him to the crime.

Paul Crotts: They kept sayin', "they don't have nothin' on him. They won't get a conver-- viction outta this.  They're just pullin' straws." 

But the defense attorney's bravado vanished with the appearance of the prosecution's star witness - a jailhouse snitch called Billy Joe Wilson - who had a gruesome story to tell.

Mark talked to him in prison, said Wilson, confessed, told him how - like a hunter - he stalked the Gilliams as they prepared for bed, how he killed them with his buck knife, how much he enjoyed it.

It took jurors just a few hours to convict Mark of two counts of first degree murder. His Mom couldn't believe it.

Linda: I automatically put my hand to my heart. ‘cause it was like a bullet went through my heart.

Her boy avoided the death penalty by one vote. Just 23.  His future essentially over.

Mark was bundled into the back of a squad car for the ride away from the courthouse. His Mom and Dad watched from the parking lot - together for the first time in years

Keith Morrison: You were chasing after the squad car?

Paul Crotts: Yeah, crying, yeah.

Keith Morrison: Have you ever been more helpless in your life?

Paul Crotts: Never.

Keith Morrison: Nor more full of self loathing?

Paul Crotts: ‘cause I helped put him there.

If not for his tough love, his interference, his big mouth, would Mark have been suspected, or charged, or convicted? He hadn't even paid for Mark's defense. Linda sold her house to pay for a lawyer.  But now Paul made her a promise.

Linda: Paul sat down beside me and said, "Linda whatever it takes. I'll do whatever it takes to prove our son is innocent.”

The furniture store would be at the heart of Paul's campaign to clear Mark's name.

Keith Morrison: In a way, this is kind of headquarters. You took calls here, tips here.

Paul Crotts:  A lot of people came in the store and gave me information.

Tim Smith was one of them.

Tim Smith: The crime scene was destroyed.

Smith was the first patrol officer to arrive at Gilliam's house after the murder. He told Paul the crime scene was compromised before police even got there. He claimed at least 15 people had tracked through.

Neighbors, the EMT people, looky-loos.

What's worse, when the detectives asked the sheriff to call in the state's mobile crime lab to help them salvage what forensic evidence might be left. He refused.

Tim Smith: I was dumbfounded. The cross contamination was so phenomenal.

Instead of a mobile crime lab, the crime scene technician went to work with a toolbox snatched from his car. He scraped blood off the floor with a knife.

Reporter Charles Jacobs is writing a book about the case.

Charles Jacobs: He did some dusting around the doors and windowsills and so forth.  But whatever he sent into the state bureau of investigation to the lab there to be tested, they sent back and said they were unreadable.

And on top of all that was the politics. Unsolved homicides had tripled in the previous year; the sheriff was feeling the heat. He told investigators their jobs were on the line if they didn't make an arrest soon.

Tim Smith: It wasn't a request. It was a demand, and they took their strongest lead and they ran with it.

Their strongest lead was the unruly tenant who lived across the street from the Gilliams: Mark Crotts.

But were there other leads detectives had overlooked? Paul hired a crack team of investigators, including 20-year veteran David Ross, to find out.

David Ross: We started interviewing people, goin' back to the-- to the area.

They kept hearing the same name again and again. Keith Saul - high school dropout and rumored drug dealer. He hung out at Mark's party barn but he seemed a little wilder than the other guys.

Paul's investigators quickly established that Keith's alibi the night of the murder was paper thin. He had asked his cousin to lie for him.

Keith Morrison: You were able to prove that he didn't have an alibi and he was trying to manufacture one?

David Ross: That's right.

Keith Morrison: And yet he wasn't part of the investigation.

David Ross: Can't answer why.

As his investigators worked, Paul brooded. And in the small town it was hard for him to keep his cool. The detectives complained that Paul was harassing them. And Paul, embarrassed now, didn't deny it.

Like the time he followed one of the investigators to a gas station:

Paul Crotts: I told him I'd take that nozzle and put it where he could flush all the bullcr*p out of him. I said, who have you put in jail this week that's innocent? And I meant what I said.

As life went on in Graham, N.C., town hero Paul Crotts was turning into something of a town crank.

And then in August 1994, there was an unexpected break in the case. Mark was granted a new trial on the grounds that his defense attorney had not been up to the job. After three years in prison, Mark was released into the custody of his father.

So, did they celebrate?  Well, not exactly.

Paul Crotts: He was gone. I thought, somebody's got him and they're gonna kill him.

In November 1994, Paul Crotts became his son's keeper.

Paul Crotts: I kept telling him, you can't go to the end of the driveway, you can't step off the driveway.

Mark had been released to his father's custody while he waited to be tried for a second time on double homicide charges. He was confined by court order to his Dad's house and horse farm.

And then one night after dinner, Mark stepped outside for a smoke and vanished. Paul searched for him – frantic.

Keith Morrison: Panicked?

Paul Crotts: --oh god, somebody's got him and they're gonna kill him.

Then he heard the groaning. It was Mark, lying in a ditch, steak knife in hand. He had stabbed himself five times in the chest.

Paul Crotts: He said, "Daddy, just let me die. Let me die. I can't go back to prison, why are they doing this to me?"

He lived, but only just. And meanwhile, Paul continued his legal battle from his furniture store, the "war room" for Mark's second trial.   He organized petitions, drafted newspaper ads, even sold these "Free Mark Crotts" t-shirts.

But that was small potatoes compared with Paul's big decision: That first lawyer not good enough?  Then he'd hire a superstar. And he did!  None other than F. Lee Bailey, flushed with victory in the O.J. case. The fee?  A quarter of a million dollars.

Paul Crotts: Never forget when he got off his plane, he said, "Are you ready for us to kick ass?" And I said, "I'm ready for 'ya. Do what's necessary.”

Trial number two began December 1995, more than five years after the murders. For the town of Graham, it was real legal theater - their small town prosecutor…

Rob Johnson: But who would seek vengeance upon these elderly folks? Who?

.. pitted against one of the most famous attorneys in the world.

F. Lee Bailey: This is tragically an unsolved pair of murders.

The state argued yet again that the crime was a revenge killing. That the only evidence they could provide to show Mark Crotts inside the Gilliam's den with a knife in his hand was the testimony of the jailhouse informant Billy Joe Wilson.  And so he was duly trotted out again, to play back that conversation he said he had with Mark Crotts.

Billy Joe Wilson: You in here for killing them old people? He said f yeh, I'm in here for killing them people.

Wilson testified that Mark confessed everything while they smoked marijuana together in his cell.

Prosecutor Rob Johnson: Did he describe to you the sensations that he was experiencing, that he experienced?

Billy Joe Wilson: He said he got off on it.

Would a jury buy that story a second time around? There was still no DNA tying Mark or the knife investigators said was the murder weapon to the scene. 

But there was something else, the state argued. A very particular signature the knife had left at the scene. Knife in hand, the prosecutor lunged dramatically again and again, showing the jury how the knife had made scratches in one of Bill Gilliam's overall buttons. In those grooves, the prosecutor argued was a trace of metal from the knife itself.

And that was the prosecution's case. Convincing? Or cannon fodder before the calm but withering assault of that lion of the defense.

F. Lee Bailey: That knife is not only incapable of having committed these murders but is not related in any way.

The prosecution's case was preposterous, Bailey countered. The knife could not have been the murder weapon because the blade was too short to make the wounds it supposedly caused.  Look at your own report, Bailey said to the medical examiner.

F. Lee Bailey: And as to wound #4 on the male, you said the wound track estimated at 6-8 inches, correct?

Medical examiner: Correct.

F. Lee Bailey: Now do you know of any cases you've had where a 5.5 inch knife made an 8 inch penetration?

Medical examiner: I can’t think of any specifically.

No, Bailey said the knife was a red herring. A distraction. He said there were far more obvious clues investigators had overlooked.

Three blood spots had been found at the crime scene but, according to this lab technician, investigators did not send them to her for analysis until after the first trial had started, a year after Mark's arrest. And no-one had bothered to collect Mark's blood for a comparison.

F. Lee Bailey: When you asked for a sample, you got it, didn’t you?

Lab technician: No, sir.

F. Lee Bailey: You didn’t?

Lab technician: No, I did not.

But now DNA testing done more than four years after the murders showed that blood scraped off the floor of the Gilliam's den did not match Mark Crotts.

F. Lee Bailey: Mr. Crotts wasn't at the crime scene, but the killer was, and he did leave evidence which was belatedly sent to investigators.

As for the story spun by jailhouse snitch, Billy Joe Wilson, Bailey set out to prove it was nothing more than a fantasy, a tale spun by a professional conman.

F. Lee Bailey: How many different people have you conned out of 1000s of dollars, Mr. Wilson?

Billy Joe Wilson: Several.

... perfectly capable of conning a jury. Or law enforcement. Bailey itemized the benefits Wilson received for his fantastic story about Mark Crotts. A letter recommending criminal charges be dropped in a nearby county. And early parole.

F. Lee Bailey: Were you not paroled the very first time you could legally be paroled?

Billy Joe Wilson: Yes, sir.

Even a personal recommendation from DA, Steve Balog, when Wilson went to rent an apartment  for four weeks Paul Crotts watched two lawyers battle over the fate of his son.

Prosecutor: Raw hatred and rage, that's why he would kill ‘em.

F. Lee Bailey: There was no hostility of any kind.

Brooding every minute on the part he had played - that secret, fateful phone call turning in his son for marijuana possession.

Two days in to jury deliberations, the courtroom was abuzz. Sheriff's deputies lined the walls. Extra security - just in case. There had been rumors of a death threat against Mark if he was acquitted.

All they could do now, father and son, was wait.

The second trial of Mark Crotts for the murder of that sweet old couple, the Gilliams, transfixed this little southern town.

The famous lawyer, F. Lee Bailey, had so galvanized opinion that he said somebody threatened to kill him. 

F. Lee Bailey: I was threatened the first day I got here.

And as the jury withdrew to consider a decision, the town was rumbling with rumors about impending vigilante justice...

Judge: if you'll hand the verdict sheet into the baliff…

And so the tension had reached fever pitch by the time the jury announced it had something to say.

We will never reach a unanimous decision in the case.

It was hung!  Bailey's expensive intervention wasn't quite enough. The judge ordered a mistrial and Mark was returned to the custody of his father. To the quiet of the horse farm. Two grown men who had knocked heads so hard and so often over the years were shackled together again. Both doing penance in a way.  Learning to forgive each other.

Mark spoke to his Dad's investigators back then.

Investigator: What do you think about your dad now?

Mark Crotts: I love him to death and I think a whole lot more of him than I ever thought of him in my whole life.

But would he still feel that way if Paul ever told him his terrible secret?

As 1996 became 97, the Gilliams had been in their graves nearly seven years. And Mark was on trial again for the third time for their murders. Mark's new attorneys were confident they could prove their client had been railroaded.

They had some new evidence - these lab results. Investigators had recovered DNA from under Alma Gilliam's fingernails - maybe she had scratched her attacker before she was killed - but prosecutors didn't get it tested until 1996, more than five years after the crime. Whose DNA was it?

David Rudolf: I don't think they ever tried to match that to anyone other than Mark.  It didn't match Mark. But they never went and looked at who else it might have matched.

This time the conclusion, for the jury, was clear. After six long years Paul Crotts heard the words he'd been praying for: "not guilty." His son was a free man .

Paul Crotts: Best moment of my life, I still feel it - I still feel it right now. He turned around and looked at me and his eyes were as big as 50-cent pieces and he came towards me and grabbed me and we embraced. And he said Daddy, I'm free. I said yeah, we're free, son. We're free.

Free, but for the nightmares.  And a constant bewilderment, says Mark, about that dreadful crime. Paul's son didn't testify at his trials but he sat down with Dateline to tell his story in his own words

Keith Morrison: Tell me what it was like to hear them say not guilty.

Mark Crotts: Oh, it was the most relievin’ words I'd ever heard in my life.

Especially he says after he'd spent so many years paying for the actions of someone else that bloody night

Mark Crotts: I just couldn’t imagine what had happened out there, you know - it just kept running through my mind - what mighta happened to ‘em.

Those two elderly people. His landlords.

Mark Crotts: I never did have a confrontation with Mr. Gilliam.

Keith Morrison: Wasn't bad blood between you two.

Mark Crotts: No, sir.

In fact court records show Bill Gilliam's eviction proceeding against Mark had been dismissed - he didn't owe any rent.

Keith Morrison: Is it possible that you really just got so tanked up one night that you committed or helped commit these murders and forgot all about it, and didn't realize what you were doing?

Mark Crotts: No sir, I don’t -

Keith Morrison: Any idea who might have been behind it?

Mark Crotts: I don’t have any idea.

Linda: He's paid a high price for something he didn't do.  And he wants to move on, and be left alone.

But moving on hasn't been easy. Mark says finding work can be tough and he's struggled with his relationships. Friends. A marriage gone bad. But Mark's devoted to his sweet little Austin...and the horse farm he runs for his dad

Mark Crotts: I'm getting older now and I know I'm not ashamed of anything in my past. I'd just like to forget some of it.

Ah, to forget. But forgetting was not something Paul seemed able to do. Not what the police did, nor the prosecutors, nor the system. And most of all, not what he had done.

And now he has decided he wants to face his son, and reveal, finally, that terrible secret of his.  Even though he knows the risk is huge.

Keith Morrison: Are you worried about how he'll look at you if you tell him?

Paul Crotts: Yeah.

Keith Morrison: Do you need to tell him?

Paul Crotts: Yeah.

Keith Morrison: Have you ever investigated something for so long in your life?

David Ross: Unh-uh, never have. I've never been around anybody like it.  I mean, he's really-- he-- he's obsessed with it.

We are sitting with Paul Crotts' private investigator.  More than ten years have gone by since Mark was acquitted of the murder of the Gilliams. But here in the furniture store, in the shadow of the offending courthouse, Paul revisits every bit of evidence, and chases down every new lead he can uncover.

He is determined, he says, to track down once and for all, the killer of Bill and Alma Gilliam.  For the sake, he says, of his son.

Keith Morrison: The law says he was not guilty. That's all you had to do. But on you went. Why? On you go now. Why?

Paul Crotts: The fact is even though we've unhandcuffed Mark, I'm gonna clear his name once and for all.

But it is not just love of son that drives Paul Crotts. A terrible guilt is gnawing at him too.

On a cold fall evening, while we sat in his kitchen, Paul made his confession. It was he, he told Mark, who found the marijuana, tipped off the cops, told them his son was capable of killing - made Mark a suspect.

Paul Crotts: It's just the fact that-- that-- I made 'im focus in on you, and-- once they focused in on you, Mark, they-- they looked no-- nowhere else.  And-- and that's haunted me through these years. I do not want you to think that I put you in that prison.

Mark Crotts: Well, I don’t, Dad. I - I my life for all that you've done to help me to free me. To get out of this. And stood by me.

Paul Crotts: I love you.

Mark Crotts: I love you too, Dad. I sure do appreciate everything. Don't feel bad about that.

Strange what brings a father and son together.

Keith Morrison: You watched him over the years, being obsessed with this case. Would you like him to lighten up a little bit--? Leave some it--

Mark Crotts: I--

Keith Morrison: --behind?

Mark Crotts: --I wish he could.  I-- it would make m-- my life a lot easier.

Keith Morrison:Wwhat do you think?

Paul Crotts: Mark, i'm not doin' it-- for you alone.  I'm doin' it for your son, too.

Paul Crotts: The case needs to be solved.  It needs to have closure.

And now Paul Crotts has an ally of sorts.

Sheriff Terry Johnson: There have been thousands, and I say thousands, of man hours put into this case.

Terry Johnson was elected sheriff of Alamance County in 2002 after pledging to clear the county's backlog of cold cases. The Gilliam case troubles him.

Sheriff Terry Johnson: I will tell you right upfront and it's embarrassing to have to say this on camera. I feel like law enforcement failed.

A bungled crime scene. An unreliable jailhouse snitch. Hardly enough evidence to indict Mark Crotts back in 1992, the sheriff says. Instead, another name jumped out at him from the case file. A name Paul's investigators had mentioned all those years ago. Keith Saul. The wild high school dropout whose alibi didn't check out.

He'd been seen near the Gilliam house that night and, the sheriff revealed, had told more than one person he'd committed the murders.

Sheriff Terry Johnson: Some of these people came forward to law enforcement, but I could not find anything that followed up and pursued any possible leads on Mr. Saul.

In fact, quite the opposite. The sheriff says one witness told him he was turned away by investigators.

And there was more - tucked into the case file was a polygraph test Saul took for police back in 1995. He failed it. -something the defense was never allowed to see

Sheriff Terry Johnson: It's easy to be a Monday morning quarterback, but it don’t make sense. It don't make sense to me.

The prosecutor says a case was never brought against Keith Saul because the evidence just wasn't there. Anything implicating him in the killing was based on rumor and innuendo.

But the sheriff has his own theory for the way things turned out.

Sheriff Terry Johnson: I do know that there was evidence Keith Sauls was supposedly an informant for the sheriff's office.

Being an informant was something Keith Saul wasn't shy to admit when he spoke to Paul's investigators.

Keith Saul: I have still been working for them to this day. What I do is buy drugs for them. I am like an informant.

But instead of investigating their long time snitch, detectives used him to investigate Mark Crotts. 

They listened in as Saul asked Mark, "Did you kill the Gilliams?". "Hell, no," said Mark.

The sheriff insists he doesn't have enough evidence to charge Keith Saul. And he never will. Because? Keith Saul is dead, killed in a traffic accident in 2008. And thus, one might quite properly assume, the end of the trail.

Well, not quite.

Because the sheriff's reading of the crime scene told him that those detectives, all those years ago,  got another thing wrong. Two people committed the murder, he says. Not one.

Sheriff Terry Johnson: Had one person gone in there they could not have controlled both those people. I feel like Mr. and Mrs. Gilliam were attacked simultaneously.

And as sure as the sheriff is that Keith Saul was in the Gilliams’ den that night, he cannot be so sure that Mark Crotts wasn't there with him. In fact some of the people who claim Keith Saul confessed to them, say he also told them Mark was there too.

Last October, the sheriff asked Mark to take a polygraph. He didn't hesitate.

Mark Crotts: I was just trying to co-operate. I mean you know, I have nothing to hide from ‘em.

And, it seems, nothing to hide from Dateline. Mark gave us access to the results of that polygraph even though he knew he had failed it. The sheriff thinks the results prove Mark has something to hide about the murders.

Sheriff Terry Johnson: He may have knowledge of it that he never told anybody. He could've been there, not actually participating or you know he could've participated. Only Mark Crotts can answer that.

Of course, polygraphs don't become evidence in court for a good reason: they're not considered to be very reliable. False negatives. False positives. Just plain false sometimes. But still.

Keith Morrison: Do you think that allows people - who were never convinced of your innocence to continue saying, "Well, I you know, we don't know.”

Mark Crotts: Well, I don't, I was found not guilty in the court system. I think that should be enough to clear that up with 'em.

Mark Crotts can't be tried again for the murders but he is all too familiar with the unforgiving court of public opinion. So is his dad.

It's a battle that has cost him so much - money, friends and more than a little peace - and it's a battle beginning all over again.

Keith Morrison: This has been a tough couple of decades.

Paul Crotts: Yeah, it has (crying).

Keith Morrison: What's it done to you?

Paul Crotts: It's made me tougher. It's not a minute goes by and I'm talking about a minute of a day, hour of a day, a week, a month, that I don't think about this.

Keith Morrison: Do you think Paul can ever let this go?

Sheriff Terry Johnson: I think-- that any parent under this situation would have a hard time of letting it go, forever, 'til the day they drew their last breath will he ever know the full truth, or will he ever accept the full truth?  I can't say.