NEW YORK — While prosecutors weigh what to do about a suspect who surprisingly surfaced this spring in the landmark 1979 disappearance case of Etan Patz, the man who was the prime suspect for years is about to go free after more than two decades in prison for molesting other children.

These two threads in the tangled story are set to cross next month, a twist that evokes decades of uncertainties and loose ends in the search for what happened to the sandy-haired 6-year-old last seen walking to his Manhattan school bus stop.

The new suspect, Pedro Hernandez, has been charged with Etan’s murder after police said he emerged as a suspect and confessed this spring. But there’s no public indication that authorities have found anything beyond his admission to implicate him, and his lawyer has said Hernandez is mentally ill.

The Pennsylvania inmate, Jose Ramos, was declared responsible for Etan’s death in a civil court, but the Manhattan district attorney’s office has said there wasn’t enough evidence to charge him criminally. After serving 25 years on child molestation convictions in Pennsylvania, he’s set to be freed Nov. 7, about a week before prosecutors are due to indicate whether they believe there’s evidence enough to keep going after Hernandez.

It stands to be a coincidence fraught with anguish for Etan’s parents, who brought a successful wrongful death lawsuit against Ramos, and for the former federal prosecutor who went to lengths to pursue him. At the same time, it offers a glimmer of vindication for Ramos, who has denied involvement in the boy’s disappearance, though authorities have said he made incriminating remarks about it.

In a letter last month to The Associated Press, Ramos said he was declining interviews while in prison but will be available to speak after his release.

Etan’s disappearance made national news and raised awareness about children’s safety, turning him into a symbol for the issue in a now-familiar response: He was among the first vanished youngsters ever pictured on a milk carton. The day of his disappearance, May 25, is now National Missing Children’s Day.

After years of investigation as far afield as Israel, an arrest was finally made on the eve of this year’s anniversary. Hernandez, who worked at a convenience store near Etan’s home when the boy disappeared, wasn’t a suspect until a tipster contacted police this spring after the case, long quiet, returned to the headlines when officials dug up a neighborhood basement looking for clues. After his arrest, the New York Police Department announced that Hernandez had admitted strangling the boy and leaving his body in a trash bag.

There has been no signal that an extensive probe in the months since has turned up further evidence against him. Hernandez’s attorney, Harvey Fishbein, raised further doubts about the case, saying Hernandez is schizophrenic and bipolar and has heard voices.

During the decades when Hernandez wasn’t on investigators’ radar, they explored many other leads and possible suspects, including Ramos.

The 69-year-old came under suspicion early on because he had a relationship with Etan’s former baby sitter, but investigators didn’t find anything solid. In the early 1980s, Ramos was arrested, though not convicted, on charges he tried to lure children to a drainage pipe where he was living. Photos of young, blond boys were found in his backpack.

Ramos then traveled the country by bus, attending gatherings of the Rainbow Family of Living Light, a loose collection of peace activists who come together around the country. He was accused of luring three boys into his bus and assaulting them at two of the group’s gatherings in Pennsylvania in the mid-1980s.

“He had thousands of dollars in ‘Star Wars’ toys on his bus. He had videotapes, and he had all kinds of materials he used to lure children inside,” Barry Adams, a longtime Rainbow member, recalled this week from his Montana home. “It was a horrendous circumstance from A to Z.”

Ramos’ record got the attention of Stuart GraBois, a Manhattan federal prosecutor assigned to help the investigation into Etan’s disappearance.

GraBois interviewed Ramos and became convinced he had assaulted and killed Etan — so convinced that GraBois helped Pennsylvania authorities get one of their convictions against Ramos. He was ultimately sentenced to a maximum of 27 years in the two cases, but got credit for time served and is being released.

Over the years, Ramos has made a series of ambiguous admissions and denials about Etan. Two jailhouse snitches claim he confessed to them, and GraBois said Ramos gave him a “90 percent confession.” But during sworn questioning in 2003, Ramos said he’d never encountered the vanished boy.

“I have nothing to hide,” he said, according to a transcript.

Etan’s parents, too, zeroed in on Ramos, pursuing him in a 2001 wrongful death lawsuit. After Ramos refused to answer some questions, a judge ruled him responsible for the boy’s death. But there wasn’t enough evidence to make a criminal case.

A DA’s office spokeswoman and Hernandez’ lawyer declined to comment on Ramos’ release, as did the now-retired GraBois. The Patzes’ lawyer didn’t respond to phone messages; the parents have asked to be left alone.

There’s no time limit for bringing charges in a murder case, so prosecutors could charge Ramos — or someone else — in future if they decide not to pursue Hernandez. But from a practical standpoint, the fact that Hernandez was charged could be grist for any other suspect’s defense.