Lawyers for the man convicted in the killing of Etan Patz, the 6-year-old Manhattan boy who went missing in 1979, have filed a motion asking the judge in the case to set aside the guilty verdict because of jury contamination.

The lawyers allege that one or more members of the jury in the case became aware that jurors from an earlier trial were regular presences in the courtroom, often seen sitting with Stan Patz, the lost boy’s father. The judge in the second trial had specifically warned prosecutors and defense lawyers not to mention the earlier trial, which ended in a hung jury after a lone juror held out for acquittal. Several of the jurors from that initial trial had spoken openly of their desire to see the accused, Pedro Hernandez, convicted, and had worked with the prosecution to prepare for the second trial.

The legal motion, filed in state Supreme Court in Manhattan on Wednesday, cited news accounts of a juror from the second trial admitting he had been informed of the presence of the former jurors from a court officer. The motion also claimed an alternate juror in the case has said he, too, became aware of the earlier jurors during the course of the second trial.

“Mr. Hernandez could not have received a fair trial once the jury was impermissibly given the information by court personnel regarding the presence of the prior jurors and/or the supportive relationship between these jurors and the Patz family,” Alice Fontier, one of Hernandez’s lawyers, said in the motion.

When Etan Patz went missing on his way to school in 1979, New York police mounted an intense manhunt, and the case became a haunting unsolved mystery for decades. Suspects came and went. Theories were floated and then abandoned. The FBI got involved. Books were written. The boy was never found.

Out of the blue in 2012, Hernandez, a former bodega clerk in the Patz family’s Manhattan neighborhood, was charged with killing the boy. Police and prosecutors said family members had claimed Hernandez had confessed several times to having done something awful as a young man, and after hours of interrogation, Hernandez confessed to luring the boy into the bodega’s basement and strangling him.

Hernandez’s lawyers called his confession a fiction, and alleged that Hernandez was mentally ill and that he had been manipulated into inventing the confession — numerous aspects of which were at odds with the accepted facts of the case.

Last month, after weeks of a retrial, the second jury convicted Hernandez, and a date for sentencing was set. But two news organizations reported that one juror, Michael Castellon, had embraced a juror from the first trial outside the courthouse. He told reporters a court officer had informed him who the woman was, and then asked that reporters not report what he had said. Efforts to reach Castellon have not been successful.

In their motion, Hernandez’s lawyers said other members of the second jury have refused to talk with them. As a result, they ask the judge, Maxwell Wiley, to either set aside the verdict or order a hearing at which the jurors would be compelled to testify.

A spokeswoman for Manhattan prosecutors said the office would respond formally in court papers by March 22.

A defense investigator, Joe O’Brien, reached an alternate who said he knew about the first jury well before deliberations.

“He could not recall if it was a general announcement to the jury or if it was just a comment passed between the two of them, but he assured me that other jurors knew this as well,” according to O’Brien’s affidavit filed with the motion. The investigator didn’t reach anyone who deliberated in the case.