PHILADELPHIA – The man who was long the prime suspect in a landmark case of a missing New York City boy is about to be released from a Pennsylvania prison where he spent more than 20 years for molesting other children.

Six-year-old Etan Patz vanished May 25, 1979, after leaving his Lower Manhattan home to go to a bus stop two blocks away. Jose Ramos, a convicted pedophile whom authorities have called the prime suspect in the case, is due to be released Wednesday from the State Correctional Institution at Dallas, in northeastern Pennsylvania, prison spokesman Michael Goyne said.

Ramos, 69, has been incarcerated at a prison at Dallas in northeastern Pennsylvania for molesting two other boys.

Investigators in Etan’s case have long been focused on Ramos, who had been dating Etan’s baby sitter at the time the boy disappeared.

Etan’s disappearance prompted a massive search that stretched as far as Israel and spawned the national movement to publicize the cases of missing children.

The blond, blue-eyed boy’s photo was among the first put on milk cartons, and his case turned May 25 into National Missing Children’s Day.

His parents never moved or changed their phone number, in case he returned. In 2001, they obtained a court order officially declaring their son dead. They have become outspoken advocates for child protection issues.

Ramos was declared responsible for Etan’s death in a civil court in 2004 but the Manhattan district attorney’s office has said there wasn’t enough evidence to charge him criminally. Ramos has denied any involvement in Etan’s disappearance.

Earlier this year, a new suspect named Pedro Hernandez was charged with Etan’s murder after police said he confessed this spring.