Searching fervently for a missing 6-year-old boy named Etan Patz, police jotted a teenage shop worker's name among those of many people they met, never expecting the clerk would become their suspect more than three decades later.

But after 35 years, Pedro Hernandez is going on trial in a murder and kidnapping case that shaped the nation's approach to missing children. Opening statements are set for Friday.

Hernandez emerged as a suspect in 2012, based on a tip and a videotaped confession that prosecutors say was foreshadowed by remarks he made to friends and relatives in the 1980s. His defense hinges on convincing jurors that the confession is false, along with suggesting that the real killer may be a convicted Pennsylvania child molester who was a prime suspect for years.

"It will be, I think, an extremely interesting case," state Supreme Court Justice Maxwell Wiley told prospective jurors earlier this month, adding that those chosen would be in for "an experience they'll never forget."

In considering evidence that reaches back to 1979, jurors will delve into a missing child case that helped inject a new protectiveness into American parenting. Last seen walking alone to his school bus stop, Etan became one of the first missing children featured on milk cartons. His parents helped advocate for legislation that created a nationwide law-enforcement framework to address such cases, and the anniversary of his disappearance became National Missing Children's Day.

The trial is expected to last up to three months and feature witnesses including Etan's mother, psychologists, an inmate informant who knows Hernandez, and possibly other informants testifying against the earlier suspect.

The seven-man, five-woman jury was chosen from a pool of about 700 people. Some openly wondered about bringing a case to trial after so many years.

"A lot of time has elapsed, and a lot of things have probably changed. ... It's 35-year-old memories," one man said during questioning earlier this week. He was not selected.

Prosecutors have spotlighted Hernandez's videotaped, hours-long confessions, in which he says he offered Etan a soda to entice him into the basement of the Manhattan convenience store where Hernandez worked. Then, Hernandez said, he choked the boy and dumped him, still alive, in a box with some curbside trash. Etan's body has never been found.

"Something just took over me, and I was just choking him," said Hernandez, 54, of Maple Shade, New Jersey. "He just kind of stood there, and I just felt bad, what I did."

Defense lawyers say Hernandez' confession is fiction, dreamed up by a mentally ill man with a low IQ and a history of hallucinations — and fueled by over six hours of police questioning before Hernandez was read his rights.

After confessing, Hernandez told a defense psychologist his memory of the killing "feels like a dream" and he wasn't sure it had really happened.

"You've heard the term 'false confession?'" defense lawyer Harvey Fishbein asked during jury questioning this week.

False confessions happen — sometimes in cases as notorious as the killing of child beauty pageant star JonBenet Ramsey — but they are hard to quantify. They factor in about 15 to 25 percent of known cases that ended in exonerations, said Allison Redlich, a University of Albany criminal justice professor.

A defense psychologist wrote that Hernandez's psychological problems and intellectual limitations make him more likely than other people to confess falsely. Prosecutors dispute that conclusion and call the confession credible.

Hernandez's lawyers also plan to point to longtime suspect Jose Ramos, a Pennsylvania prisoner who dated a woman who sometimes cared for Etan. Authorities said Ramos made incriminating statements when questioned about Etan in the 1980s, though he never confessed to killing the boy. Ramos has denied it, but a civil court found him liable for Etan's death in 2004 after Ramos stopped cooperating with questioning.

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Associated Press writer Colleen Long contributed to this report. Reach Jennifer Peltz on Twitter @jennpeltz.