NEW YORK » The man charged with killing a 6-year-old boy in 1979 made a false confession and will plead not guilty in a case that catalyzed the missing-children’s movement, his lawyer said today.

Pedro Hernandez’s admission in May to suffocating Etan Patz was a stunning turn in one of the most notorious and vexing cases in New York City history, prompting the first arrest ever in the case. But he is mentally ill, and his statements "are not reliable," his lawyer, Harvey Fishbein, said after Hernandez made a brief court appearance today.

"The really sad part of this case is that it will take time, it will take money … and it will not tell the city what happened to Etan Patz," Fishbein said.

An ashen-looking Hernandez stood in handcuffs during the hearing and never spoke. His wife and daughter were in the courtroom but left without talking to reporters. Hernandez has been held without bail since his arrest.

While Fishbein has said Hernandez is schizophrenic and prone to hallucinations, the attorney said the New Jersey man is fit to stand trial. Legally, competence for trial doesn’t mean a defendant’s mental state can’t be part of his defense.

But prosecutors say an exhaustive post-arrest investigation found enough evidence to seek an indictment and proceed to trial.

"We believe the evidence that Mr. Hernandez killed Etan Patz to be credible and persuasive, and that his statements are not the product of any mental illness," Erin M. Duggan, spokeswoman for Manhattan District Attorney Cyrus R. Vance Jr., said Wednesday.

A judge set a Dec. 12 date for Hernandez to enter a plea.

Etan’s disappearance is legend. It led to an intensive search and spawned a movement to publicize cases of missing children. His photo was among the first put on milk cartons, and his case turned May 25 into National Missing Children’s Day.

Hernandez, 51, was a teenage stock clerk at a convenience store when Etan disappeared on his way to school on May 25, 1979. Hernandez was a married father with no criminal record and living in Maple Shade, N.J. when police approached him based on a tip earlier this year.

Investigators say he told them he lured the boy into the convenience store with the promise of a soda. He allegedly said he led the child to the basement, choked him and left his body in a bag of trash about a block away.

Following the arrest, court hearings for Hernandez were postponed for weeks, with both sides saying they were continuing to investigate. The prosecutor’s office said in September it wanted time to keep going "in a measured and fair manner."

Authorities seized a computer and a piece of old-looking children’s clothing from Hernandez’s home, scoured the basement of the building where he had worked in what was then a grocery store and interviewed his relatives and friends — but nothing incriminating came of it, according to a person familiar with the investigation.

The person wasn’t authorized to discuss findings not yet made public and spoke to The Associated Press on condition of anonymity.

Under New York state law, a confession can be enough to convict someone as long as authorities can establish that a crime occurred.

False confessions are a longstanding legal phenomenon. Examples range from the more than 200 people who came forward to claim to kidnapping the infant son of aviator Charles Lindbergh in the 1930s to the 2006 episode in which a man falsely said he’d killed JonBenet Ramsey, the 6-year-old beauty queen found dead in her parents’ Colorado home a decade earlier.

Fishbein said he planned to have expert witnesses explain why people sometimes admit to crimes they didn’t commit.

"It’s a hard concept to understand. But it’s a reality. And it’s a scary reality," Fishbein said.

Asked whether Hernandez still believes his confession, the attorney answered, "He’s pleading not guilty."

From the outset, Hernandez’s his wife, Rosemary, told investigators that he had a history of hallucinations, said an attorney representing the family, Robert Gottlieb.

The wife and the couple’s daughter, Becky, "have lived with him and seen firsthand that type of behavior," Gottlieb told reporters outside court.

"They support him 1,000 percent," the lawyer added. "They don’t believe the so-called confession."

Etan’s parents had a court declare the boy legally dead more than a decade ago, allowing them to sue convicted child molester Jose Ramos in the boy’s death.

Ramos was found responsible — a ruling made because he didn’t entirely cooperate with questioning during the lawsuit — but it’s unclear how that finding could now factor into the prosecution of Hernandez.

Ramos, now 69, had been dating the boy’s baby sitter in 1979 and was considered a suspect. He was later convicted of molesting two different children and was in prison in Pennsylvania prison for more than a quarter-century.

Ramos had been scheduled to be released last week, but he was immediately rearrested on a charge of failing to register properly as a sex offender; authorities said he’d lied about where he planned to live, giving an address a relative vacated long ago. He was ordered to stand trial today for allegedly providing authorities with a bogus address.

Etan’s father, Stanley Patz, said Wednesday that the family wasn’t commenting on the case.