NEW YORK (AP) - The investigation into the disappearance of 6-year-old Etan Patz has stretched through decades and countries, from basements to rooftops and seemingly everywhere in between.
No one has ever been charged criminally - and the little boy with sandy brown hair and a toothy grin was declared dead in 2001.
This week, after more than a decade of relative quiet, the case suddenly ran hot again, after a cadaver-sniffing dog picked up a scent in an old basement down the street from the boy's home in New York City.
By Saturday, investigators had finished ripping up the basement's concrete floor with jackhammers and saws, and were digging through the dirt in hope of finding the boy's remains, or any other evidence.
So far, authorities haven't given any outward sign that they've found anything.
"Law enforcement is always cautiously optimistic," said Tim Flannelly, chief FBI spokesman in New York. "But this is one lead of many."
It's not clear what, if anything, the dig will turn up, but the investigation has reached similar highs before - only for the trail to go cold for years at a time.
Etan vanished on May 25, 1979, while walking alone to his school bus stop for the first time, two blocks from his home in New York's SoHo neighborhood.
There was an exhaustive search by the police and a crush of media attention. The boy's photo was one of the first of a missing child on a milk carton. Thousands of fliers were plastered around the city, buildings canvassed, hundreds of people interviewed. SoHo was not a neighborhood of swank boutiques and galleries as now, but of working-class New Yorkers rattled by the news.
"No one could understand how it could've happened, at that time, we all felt safe, we were a little community," said Sandie Vega, who was Etan's age when he disappeared. "We also thought it must've been someone from the outside, no one we knew could take him."
Yukie Ohta, now 43, remembers police coming to her door to talk to her about the boy's disappearance. Her sister had gone to a child's play group with Etan, in the very basement police are searching. By the time he disappeared, the children's collective had moved and the space was being used by a handyman.
"I didn't really know anything helpful," Ohta said.
No one knew enough. Etan's parents, Stan and Julie, offered a $25,000 reward for information leading to the boy's whereabouts, and sightings were frequently reported, to no avail. In 1986, a child resembling Etan was spotted in Israel, which prompted detectives to circulate his photo there. Nothing came of it.
A name gradually emerged as a possible suspect: Jose Ramos, a drifter and onetime boyfriend of Etan's baby sitter. In the early 1980s, he was arrested on theft charges, and had photos of other young, blond boys in his backpack. But there was no hard evidence linking Ramos to the crime.
Missing persons cases, like homicides, are generally considered cold after six months, but they're never closed. And with seemingly no new leads, the case would go quiet for years. In three decades, 10 detectives have been assigned to head up the case. The FBI and police are working jointly.
"Those cases are still maintained by someone, but the attention they get diminishes over time," said Joseph Pollini, a retired NYPD lieutenant in the cold case squad, now a professor at John Jay College of Criminal Justice. "There's often nothing you can do, when you have no new leads."
A former federal prosecutor who had worked on the case declared in 1998 that he believed Ramos was behind Etan's disappearance and death. Ramos, now serving a prison sentence in Pennsylvania for abusing an 8-year-old boy there, has denied killing Etan.
Police investigated leads to Ramos at various points, including a 2000 search of the basement of the building where he lived in 1979. They dismantled the furnace and searched it for DNA. But they found only animal traces.
By the next year, father Stan Patz, who never moved or even changed his phone number in the hope his son would reach out, had Etan declared dead in order to sue Ramos in civil court. He was tired of waiting for justice, he said at the time.
A civil judge in 2004 found him to be responsible for the disappearance and presumed death of the boy, after he disobeyed her orders to answer deposition questions under oath for a lawyer representing Etan's parents.
The ruling provided a tiny measure of comfort to the family. But the criminal case continues, and prosecutors lacked enough evidence to charge Ramos criminally.
The case was quiet until 2010 when new district attorney Cyrus R. Vance Jr. said he was going to revisit it.
Ramos is scheduled to be released from prison in November. His pending freedom is one of the factors that has given new urgency to the case.
But the focus has shifted to the basement that had been used at the time as a workspace for a handyman named Othniel Miller. He was interviewed after the boy went missing. Investigators noticed at the time that the basement had a fresh concrete floor; his space was searched then but never dug up.
He gave investigators an alibi for the time of Etan's disappearance, though they are giving his account of the day a fresh look, a person familiar with the investigation said Saturday. The person spoke on condition of anonymity to discuss the ongoing investigation
Law enforcement officials have spoken to him as recently as Wednesday, and one interview prompted them to take a closer look at the space, the officials said, speaking on condition of anonymity because the case was ongoing.
The 75-year-old Miller hasn't been named a suspect, and his lawyer says he has nothing to do with the case.
The attorney, Michael C. Farkas, declined to comment Saturday.
"I couldn't believe it, and still don't, not yet anyway" said Cass Collins, who lived in the neighborhood at the time. "He was always around, he would work in our loft, he was near our kids all the time. It would be shocking."
The 13-by-62-foot basement space being searched sits beneath several clothing boutiques. Investigators began by removing drywall partitions so they could get to brick walls that were exposed in 1979. The work will continue through the weekend. About 50 law enforcement agents including forensics experts and an anthropologist are on scene. While cadaver-sniffing dogs are capable of detecting scents much older than 33 years, it's also possible the dog picked up an animal scent or was plain wrong.
The cobblestone street remained closed off and was a veritable media circus, with trucks and crews parked along the curb and gawking tourists stopping to snap photos.
The Patz family hasn't commented or turned up near the site, though it's visible from their home - they've seen the circus before.
"To the hardworking and patient media people, the answer to all your questions at this time is no comment," read a handwritten note outside their door. "Please stop ringing our bell and calling our phone for interviews."
"Stan Patz, 3E."
Associated Press writers Samantha Gross, Tom Hays and Jennifer Peltz contributed to this report.