May 26, 2010 -- The 31-year-old case of Etan Patz, the little boy who disappeared on his way to a school bus stop in downtown Manhattan, has been reopened, a spokeswoman for the New York district attorney confirmed to ABC News.
On National Missing Children's Day, Manhattan District Attorney Cyrus Vance agreed to investigate the iconic case, which sparked a national campaign to find missing children and marked profound changes in how missing children cases were investigated.
Vance took office in January after the retirement of District Attorney Robert Morgenthau, who had declined to proceed with the case, citing insufficient evidence.
For the Patz family, it has been more than three decades of agonizing investigations and years of wondering what happened to their blond son with the gorgeous smile, and questioning why the man they believe is responsible for his kidnapping -- Jose Antonio Ramos -- has never been held criminally liable.
"I still gag with fear that this child must have felt ... when he realized he was being betrayed by an adult," Etan's father Stan Patz told ABC News' "20/20" in an interview last May.
Former federal prosecutor Stuart GraBois, who fought to solve the disappearance of Etan Patz for more than 20 years, told ABC News he agrees with Vance's decision.
"I'm quite pleased that the DA's office sees fit to reopen the investigation and hopefully they'll also see fit to indict and convict Jose Antonio Ramos for the abduction and murder of Etan Patz," said GraBois, who took over the investigation in 1985, but was never able to prosecute the case.
Ramos, an imprisoned child molester whose former girlfriend had worked for the Patzes, walking Etan to and from school during a bus strike, is still the main suspect in the case.
Investigators connected Ramos, a convicted pedophile, to the Etan Patz case. Etan's body was never found, but he was declared dead in 2001. In a 2004 civil suit, a New York judge ruled Ramos responsible for Etan's death -- a charge he denied. Ramos is currently serving time in a Pennsylvania prison for molesting an 8-year-old boy in an unrelated case. He is expected to stay behind bars until 2012.
Missing Child: The Search for Etan Patz
On May 25, 1979, six-year-old Etan Patz disappeared in the Soho neighborhood of New York City walking to the school bus stop. It triggered a massive search where neighbors and police covered the city with missing child posters featuring Etan's smiling face. But there were few leads.
Etan's father -- a professional photographer -- used a collection of photographs he had taken of his son in the effort to find the missing boy. Stan Patz's photos of Etan would be printed on countless missing child posters, milk cartons, and even projected on screens in New York's Times Square.
At first, detectives considered the Patzes as possible suspects, but they quickly determined the parents had no involvement.
'The 90 Percent Confession'
From early on, GraBois believed that Ramos was involved in Etan's disappearance. Some boys had accused Ramos of trying to lure them inside a drainpipe, where he lived in 1982 in the Bronx. When police searched the drainpipe, they found photographs of Ramos and young boys who resembled Etan, but no charges were pressed and Ramos vanished. GraBois eventually found out that Ramos was in custody in Pennsylvania in connection with an unrelated child molestation case.
GraBois brought Ramos to New York to meet face-to-face. Ramos had no idea why he was there. Out of the blue, GraBois asked him directly, "How many times did you have sex with Etan Patz?" According to GraBois, Ramos "froze" and said, "I'll tell you everything."
Ramos' response is now known as "the 90 percent confession." He admitted taking a young boy back to his apartment for sex on the day Etan disappeared and told GraBois he was 90 percent sure it was the boy he later saw on TV. As GraBois pointed out, "the only boy missing and on television that evening was Etan Patz." GraBois said that at that moment he "believed we had the right guy."
But the confession was not complete. Ramos did not use Etan's name and he claimed he had "put the boy on a subway."
GraBois himself would never hear the last 10 percent of the story that he was after. However, during Ramos' time in lockup, two convicted criminals, claimed to have knowledge about Ramos and volunteered to try to get more information from Ramos about the Patz case.
One informant told GraBois and FBI agent Mary Galligan that Ramos told him that he knew what happened to Etan. Ramos had even drawn a map of Etan's school bus route, pointing out that he knew Etan's stop was the third one.
In an interview with 20/20 on the thirtieth anniversary of his son's disappearance, Stan Patz said each year he sends a special reminder to Ramos in prison that the case is not forgotten. He mails one of the old lost child posters to Ramos with a simple typewritten line on the back that reads: What did you do to my little boy?
ABC News' Emily Friedman contributed to this report.