(Reuters) -- A judge declared a mistrial on Friday in the marathon trial of Pedro Hernandez, who had confessed to killing Etan Patz, the New York City boy whose 1979 disappearance raised awareness of the plight of missing and abducted children and their families.

Immediately after state Supreme Court Justice Maxwell Wiley's mistrial ruling, Assistant District Attorney Joan Illuzzi-Orbon requested a second trial for Hernandez.

The decision came after the jury, in its 18th day of deliberations at the court in Manhattan, told the judge for a third time that it was unable to reach a unanimous verdict. On two previous occasions during the 10-week trial, Wiley ordered the panel to resume deliberations.

Eleven jury members were in favor of conviction, jurors said at a media briefing. Only one held out for acquittal.

Patz vanished on May 25, 1979 as he walked alone for the first time to a school bus stop in the Soho neighborhood of Manhattan.

Hernandez, a former deli worker now 54 years old, confessed to police in 2012 that he choked the 6-year-old Patz, stuffed him in a box and left him in a New York alley.

"We are frustrated and very disappointed that the jury has even unable to reach a decision," said Stan Patz, the boy's father. "Our long ordeal is not over."

After hearing trial testimony, "we have come to the conclusion that Pedro Hernandez is guilty of crimes to which he confessed, beyond any reasonable doubt," Patz said after the jury was dismissed.

In a statement echoing the father's view of the case, Manhattan District Attorney Cyrus Vance said, "there is clear and corroborated evidence of the defendant's guilt beyond a reasonable doubt."

In the U.S. justice system, a defendant is presumed innocent of a crime, and the jury must determine guilt beyond a reasonable doubt.

Defense attorney Harvey Fishbein said, "I'm sure the Patz family is very interested in a resolution in this case. We firmly believe Pedro Hernandez is not the right man."

Lawyers for both sides will meet in court on June 10 to discuss what happens next and confirm the decision to move ahead with a retrial.

The defense had tried to put blame on Jose Ramos, who dated a Patz family babysitter and was long considered the prime suspect. Ramos is serving a prison term after being convicted of sexually abusing boys.

A judge found Ramos legally responsible for the death of Patz in a 2004 civil lawsuit brought by the Patz family.

Patz's disappearance brought attention to the issue of missing and abducted children, and his picture was one of the first to appear on milk cartons in the United States.

"He represents a moment in this city and this country where there was a loss of innocence, trust, a way of life," prosecutor Illuzzi-Orbon said in her summation to the jury. "Etan, by his death, saved many, many children from a similar fate."

Hernandez's defense attorneys had argued that Hernandez is mentally ill and his confession was coerced by police.

Hernandez did not take the witness stand during the trial.

The crime long haunted New Yorkers who can recall the massive search for the missing blond boy, who was never found. He was declared dead in 2001.

His mother, Julie Patz, told the jury that her young son had been outgoing and trusting.

"Everyone he met was a friend and a nice person," she said.

Hernandez was arrested in 2012 on a tip that he had confessed to a church prayer group in New Jersey.

In a confession videotaped by police, he described luring Patz into the deli where he worked, taking him to the basement and strangling him.

"I wanted to let go, I just couldn't let go. I felt like something just took over me, and I was choking him," Hernandez said on the videotape.

The boy went limp, but was still alive when he disposed of the body, Hernandez said.

"He was still gasping," the man said.

Three members of the church prayer group testified against Hernandez, recounting his tearful confession at the end of a daylong summer religious retreat in 1979.