The abduction happened 27 years ago, at a time when parents routinely left their children playing in the toy store, unattended, and continued shopping.
But when Reve Walsh returned to pick up her 6-year-old son, he wasn't there. Over the mall loudspeaker, the plea came: "Adam Walsh, please come to customer service."
Two weeks later, fishermen discovered the boy's severed head in a canal 120 miles away from the Hollywood mall. His body was never found.
The case led to advances in police searches for missing youngsters and a notable shift in the view parents and children have of the world.
On Tuesday, police closed their investigation. They said a serial killer who died more than a decade ago in prison was responsible for Adam's death. They admitted making crucial errors in the case and apologized to the Walshes.
But Adam's death, and his father's transformation from a hotel developer to an activist, helped put missing children's faces on milk cartons and in mailboxes, started fingerprinting programs and increased security at schools and stores.
It spurred the creation of missing persons units at every large police department. And it prompted legislation to create a national center, database and toll-free line devoted to missing children. It also prompted the television program "America's Most Wanted," hosted by John Walsh, which brought such cases into millions of homes.
"In 1981, when a child disappeared, you couldn't enter information about a child into the FBI database. You could enter information about stolen cars, stolen guns but not stolen children," said Ernie Allen, president of the Center for Missing and Exploited Children, which was co-founded by John Walsh. "Those things have all changed."
Jim Larson of Orlando witnessed the effects of John Walsh's work. His wife, Carla, was abducted in a grocery store parking lot one afternoon in 1997 and was raped and strangled. He credits "America's Most Wanted" with catching her killer.
"Maybe, eventually, they would have gotten there," Larson said of police. "But it seemed like right after the show aired, calls were coming in and leads were followed and they got him."
The man convicted in the killing, John Huggins, is now on Florida's death row.
'Extremely paranoid' parents?
Others are more hesitant to dole out credit. John Walsh's efforts, said Mount Holyoke College sociologist and criminologist Richard Moran, have made children and adults exponentially more afraid of the world.
"He ended up really producing a generation of cautious and afraid kids who view all adults and strangers as a threat to them and it made parents extremely paranoid about the safety of their children," Moran said.
Police closed the case without any new evidence or even anyone they could charge with the crime.
"For 27 years, we've been asking who can take a 6-year-old boy and murder and decapitate him. We needed to know. We needed to know," said John Walsh. "The not knowing has been a torture, but that journey's over."
Police said the man long considered the lead suspect, Ottis Toole, was conclusively linked to the murder, but largely with circumstantial evidence.
"Our agency has devoted an inordinate amount of time seeking leads to other potential perpetrators rather than emphasizing Ottis Toole as our primary suspect," said Hollywood Police Chief Chadwick Wagner. "Ottis Toole has continued to be our only real suspect."
Authorities made a series of errors over the years, losing the bloodstained carpeting in Toole's car — preventing DNA testing — and the car itself. Wagner launched a fresh review of the case when he became the department's chief last year.
In 1997, Adam's father, John Walsh, released the book "Tears of Rage," that criticized the police department's work.
"So many mistakes were made," he said. "It was shocking, inexcusable and heartbreaking."
John Walsh has long thought Toole was responsible, saying investigators found a pair of green shorts and a sandal similar to what Adam was wearing when he was abducted.
"I have no doubt," John Walsh said. "I've never had any doubt."
Toole confessed to the killing, but later recanted. He claimed hundreds of murders, but police determined most of the confessions were lies. Toole's niece told John Walsh her uncle gave a deathbed confession to the crime.
Toole died in prison of cirrhosis in 1996 at the age of 49. He was serving five life sentences for murders unrelated to Adam's death.