Long before there was an official confession, there were the confidants: friends and relatives who heard a disturbing story about killing a child from the man now on trial in the 1979 disappearance of Etan Patz.

Most didn't tell authorities until police approached them decades later. And during testimony this week, they've had to explain why.

There was the neighbor whom Pedro Hernandez told in the 1980s about strangling an unnamed boy, the ex-wife who says Hernandez not only made a similar admission to her but also kept a piece of Etan's missing-child poster, and the prayer circle where Hernandez broke down in tears and said he'd abused a boy, then killed him.

Prosecutors see their testimony as evidence bolstering Hernandez's own 2012 confession to authorities in one of the nation's most prominent missing-child cases. His defense says all his admissions were false.

Hernandez's confidants gave varied reasons for not alerting authorities: They didn't take him seriously; they didn't feel they had enough information to act. Psychology experts also point to the well-known bystander effect, in which witnesses don't intervene in crimes or emergencies, particularly when they're in a crowd.

"From a social psychological perspective, it makes perfect sense why people might not have gone to the police," says Daniel M. Day, a psychology professor at Ryerson University in Toronto.

Hernandez was working at a nearby convenience store when Etan vanished on his way to school May 25, 1979. The anniversary is now National Missing Children's Day.

Hernandez became a suspect only after his brother-in-law Jose Lopez told police in 2012 that Hernandez had confessed years earlier to killing a child in New York. Then Hernandez confessed to authorities.

The 54-year-old resident of Maple Shade, New Jersey, has pleaded not guilty. His lawyers say his accounts of killing Etan were imaginary and driven by mental illness that makes him blur reality with fantasy. Prosecutors deem his confession credible and say his earlier admissions were efforts to unburden himself without being specific enough to get caught.

Praying alongside at least four people at a New Jersey religious retreat in the summer of 1979, Hernandez started crying and made an admission that matched some of what he told authorities on video 33 years later: He gave a child a soda, took him to the store basement and choked him, prayer group member Pieto Conception and others testified. But Conception said Hernandez also admitted abusing the boy. Hernandez denied molesting Etan to police.

Mark Pike, Hernandez's former neighbor in Camden, New Jersey, testified that during a 1980 front-porch chat, Hernandez described how a boy in New York threw a ball at him, and "he lost it" and strangled the child.

"I just said, `Why?"' Pike recalled. Hernandez gave no answer, he said.

About two years later, Hernandez told 16-year-old girlfriend Daisy Rivera he wanted to come clean about "something terrible" -- he had strangled a "gringo muchacho," or white guy, who offended him while in New York.

Later, during their brief but contentious marriage, she said, she found the missing-poster photo of Etan in a shoe box that Hernandez had and asked him about it but didn't consider whether it was linked to the story he had told her.

She didn't tell authorities about that story, she said, because she had no proof. Pike simply "didn't believe it at the time," thinking Hernandez was trying to seem tough. Conception noted that he hadn't actually witnessed the crime and said he had felt Hernandez "wasn't doing well" mentally.

Hernandez's confidants -- particularly in the prayer group -- might have been feeling psychological forces that factor into the bystander effect, experts said.

Researchers have found bystanders tend to be slower to act when an emergency seems ambiguous -- like, perhaps, a confession to a killing without details. Bystanders also may reason it's not their responsibility to respond, or they may feel reluctant to react when others don't.

"It might seem obvious -- `Oh, you should tell the authorities,"' notes Villanova University psychology professor Patrick Markey, but "it's hard for us to know what we'd actually do."

The American justice system generally doesn't require people to disclose information to police, though some jurisdictions require eyewitnesses or certain professionals -- such as doctors or child welfare workers -- to report certain categories of crimes. Legal and religious traditions provide considerable protection for confessions made one-on-one to a clergy member. That doesn't apply to prayer groups, but many operate on an understanding of privacy.

Ambiguity initially stopped Lopez from going to police, he said, because he didn't have enough information and had heard about Hernandez's statements only secondhand.

But the story stuck with him. And after getting Internet access and finding out about Etan's case in 2000, he tried calling missing-children's advocates twice, but no one took him seriously, he testified.

Finally, after seeing a new round of news reports about Etan's case in spring 2012, he decided to try once more. He called the New York Police Department, thinking "maybe someone would listen to me."

And he was right.