IE 11 is not supported. For an optimal experience visit our site on another browser.

Florida man's death was blamed on alligators at first, but his mom's determination led to the truth

Mike Williams went missing days before Christmas in 2000. After his mother, Cheryl, pushed for an investigation, a police probe led to his wife's conviction.

It was a few days before Christmas 2000.

A pre-dawn duck hunting trip was Mike Williams' time alone before a busy anniversary weekend with his wife, Denise. As he had done so many times before, Mike got up around 3 a.m. and left his home in Tallahassee, Florida, for Lake Seminole about an hour away.

This was duck season, and he had to be on the water before dawn and in his spot to start hunting legally at first light. Mike told his mom, Cheryl, that Lake Seminole was a special place for him.

"A lot of times, he'd go to Lake Seminole just to sit there in his boat and watch the ducks come in. He said, ‘Mom, a lotta times I don't even — I don't even have my gun in the boat,'" Cheryl Williams recalled.

But Williams never came home from this trip. It was as if he had vanished. By late afternoon, his wife called around asking if anyone had seen or heard from him. The answer was no.

Watch more on this on NBC News' "Dateline" on Friday, 10 pm ET/9 pm CT.

Williams' brother, Nick, and dozens of others went to the lake to search, along with officials from the Florida Fish and Wildlife Conservation Commission. Two helicopters and airboats were brought in.

Late that night, Williams' best friend Brian Winchester found his hunting buddy's boat. The two had known each other going back to high school.The boat was empty, full of gas, and Williams' duck decoys had never been deployed. That meant he had not been out on the lake long.

Mike Williams and Denise wedding photo.Russell Grace

The search turned up nothing for days. Finally, on the 10th day, a searcher found what looked like Williams' hat floating on the water. For the next 56 days, they searched and couldn’t find his body. It appeared he’d drowned. That could happen easily in the dark on Lake Seminole. Speculation from the Fish and Wildlife officers on the scene, as well as experienced hunters, was that Williams hit a tree stump, fell in the water, and -- in a horrifying possibility -- was eaten by one of the many alligators that inhabit the lake.

But that theory was shot down because of the weather. A cold front brought in temperatures in the 20s that first night, and the cold weather continued for days. Alligators don’t do much when it’s cold, according to Fish and Wildlife officer Alton Ranew. "His metabolism is down so low, he don't wanna eat. They're like a bear. They go into hibernation. They stay there the whole winter," Ranew said, describing alligator behavior.

Then six months after Williams went missing, something literally surfaced. It was his chest high waders and a hunting jacket. None of the clothing had any tears or bite marks, meaning no signs of an alligator attack.

His wife, Denise, had been left to fend for herself and their 18-month-old daughter, Anslee. Fortunately, Williams, a successful real estate appraiser, had taken out a $1.75 million life insurance policy.

His buddy Winchester, an insurance broker who had sold him some of the policies, helped Denise find a lawyer to get a presumptive death certificate in only seven months, a process that usually takes five years in Florida.

But one person was not satisfied that every effort had been made to find Williams — his mother.

Cheryl Williams believed her son might still be alive, but at a minimum she wanted police , not just Fish and Wildlife officers, to do an investigation. But no one would. She asked for the media's help to publicize his story, and took out advertisements in the local newspaper and paid for billboards. She stood on street corners with handmade signs asking for help to find her missing son.

Denise Williams during her trial for the murder of her husband Mike Williams, in Tallahassee, Florida on Dec. 12, 2018.Alicia Devine / Tallahassee Democrat via AP pool

Eventually, the Florida Department of Law Enforcement said it would investigate. Then, in 2005, five years after Mike Williams went missing, the rumor mill was abuzz. Denise Williams married Brian Winchester, Mike’s best friend, who divorced his wife a few years earlier.

After the wedding, investigators focused on Winchester and Denise. Cheryl Williams told investigators that Denise would not allow her to see her granddaughter, Anslee, if she did not stop pushing for this investigation.

Quoting Denise, Cheryl said she told her if you stop this investigation, you can see granddaughter Anslee again. Cheryl told Denise, “I couldn't stop this investigation if I wanted to.” Denise followed through on her promise and cut Cheryl off from seeing Anslee.

Then in 2012, the couple separated. Four years later, Winchester kidnapped Denise at gunpoint. Authorities thought he was going to kill her to keep her from telling police what she might know about Williams' disappearance.

After his arrest for the kidnapping, Brian’s attorney was able to get a deal for him. If he showed authorities where he buried the body and gave them the full story of how Mike Williams was murdered, they would only charge him with the kidnapping and not the murder.

In his confession, he admitted that he and Denise Williams plotted to kill Denise’s first husband, Mike. He testified before a grand jury and prosecutors got a first-degree murder indictment against Denise, and Denise only. In exchange for his cooperation, Brian was sentenced to 20 years in prison on the kidnapping charge.

At Denise’s trial, he testified that he and Denise had been lovers for three years before the murder, and that they both plotted it so she could also collect the insurance payout.

Winchester was the state’s star witness. "She would not get divorced. And so, she basically said, 'There's only one solution.'"

In December, almost 18 years to the day, a jury took eight hours to find Denise guilty of first-degree murder. It carries a life sentence without the possibility of parole. In addition to losing her father, daughter Anslee, now 19 and a college student, has a mother who will never be free.

Denise’s lawyer said he would appeal.