Six-year-old Etan Patz vanished on May 25, 1979. One of the most extensive missing-child searches was mounted to find him, but two decades later, the boy was officially declared dead. No one has ever been arrested. 
 
 FILE - In this May 18, 1985 file photo, Stanly Patz, left, holds a photo of his son Etan, as he poses for a photo with his other son Ari, at their home in New York. Etan Patz vanished on May 25, 1979.... (Associated Press) 
 
 Now, the Manhattan district attorney's office will take a fresh look at the evidence collected against the prime suspect, a convicted child molester serving 20 years in prison in Pennsylvania. 
 
 By looking into the cold case, Cyrus R. Vance Jr. will be making good on a campaign promise. A spokeswoman for Vance said Wednesday she could not comment further on an open investigation. 
 
 Etan Patz (pronounced AY'-tahn payts) vanished while walking from his lower Manhattan home to a bus stop two blocks away. His disappearance spawned the national movement to publicize the cases of missing children. His photo was the first put on a milk carton, and his case turned May 25 into National Missing Children's Day. 
 
 The longtime former district attorney, Robert Morgenthau, said repeatedly he didn't have enough evidence to charge anyone. But Etan's father, Stan Patz, said that while there is little forensic evidence, he believes there is enough to convene a grand jury and get an indictment. 
 
 "All we have been asking for is the district attorney to take a good look at the information," Patz said. "I realize this is not like `CSI.' That's why it's been a tough case all along. But there is enough evidence that a competent attorney can use to prosecute." 
 
 Jose Ramos, who had dated Etan's baby sitter, has been the prime suspect all along, according to the boy's family. Ramos allegedly admitted to Pennsylvania authorities that he tried to molest Etan on the day of the child's disappearance but has denied harming him. It was unclear Wednesday if Ramos has an attorney, and Ramos was unreachable at the prison. 
 
 After Etan's disappearance, his parents kept the same number and stayed in the same SoHo apartment, in case he returned. But in 2001, after waiting 22 years, they obtained a court order declaring the boy dead. 
 
 In 2004, a Manhattan judge ruled Ramos was responsible for the boy's disappearance and presumed death, after the inmate ignored orders to answer deposition questions for a lawyer for the boy's parents. He was later ordered to pay $2 million to Etan's family. 
 
 Ramos is to be released in 2012 after a 20-year sentence for sexually abusing an 8-year-old boy, bringing a certain urgency to the case, which was never officially closed, the boy's father said. At least one FBI agent and a New York Police Department liaison is assigned to the case. 
 
 Patz is hopeful a fresh pair of eyes will yield some results. 
 
 "He (Vance) says he's willing to do that, and the fact he's willing to say it in public is very encouraging," Patz said. 

 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. 
 
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 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. 
 
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 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. 
 
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 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.
– Manhattan's district attorney is taking a fresh look at the evidence in one of America's most famous missing child cases. Six-year-old Etan Patz vanished on his way to a Manhattan bus stop in 1979. A huge search was mounted, and Patz became the first missing child ever to be shown on a milk carton, but no trace of him was ever found. Jose Ramos, a convicted child molester currently serving time in Pennsylvania whose former girlfriend once worked for the Patzes, has long been the prime suspect—and Patz's father Stanley is hoping for an indictment at last, ABC reports. Ramos, who is due to be released in 2012, has admitted attempting to molest a young boy on the day Patz disappeared but didn't use Etan's name, and insisted he "put the boy on a subway." "All we have been asking for is the district attorney to take a good look at the information," Stanley Patz, who each year sends Ramos one of the old missing child posters with "What did you do to my little boy?" written on back, tells the AP. "I realize this is not like CSI. That's why it's been a tough case all along. But there is enough evidence that a competent attorney can use to prosecute."