New York (CNN) -- A former Manhattan store owner named Pedro Hernandez claims he strangled 6-year-old Etan Patz, according to a law enforcement source with knowledge of the investigation.
The boy's disappearance 33 years ago Friday helped spawn a national movement to raise awareness of missing children, which involved a then-novel approach of splashing an image of the child's face across thousands of milk cartons.
Police were tipped off to Hernandez by someone who knew him, and whom Hernandez had confided in, the source said.
In her book detailing the investigation, author Lisa Cohen describes the plan Etan had the day he went missing. Just prior to his disappearance, according to the book, Patz told his parents that he planned to stop at a store to buy a soda with a dollar that he'd earned by helping a neighborhood carpenter. It's not clear which store he meant.
The carpenter, Othniel Miller, 75, met Etan the day before and was recently the focus of media attention when investigators announced they were again questioning him.
"Mr. Miller is relieved by these developments, as he was not involved in any way with Etan Patz's disappearance," said Miller's attorney Michael C. Farkas. "At the same time, Mr. Miller is very pleased that those responsible for this heinous crime may be brought to justice, and the Patz family may finally have the closure they deserve."
Hernandez's claim is considered "a good lead," the source said, but it's unclear where the new development will take the decades-old case.
However, a separate law enforcement source said Thursday that Hernandez's claims are being treated with "a healthy dose of skepticism." He was picked up Wednesday in New Jersey, two law enforcement sources added.
Overheard on CNN.com: Face on milk carton chipped away at our innocence
Hernandez, who has not been charged with a crime, had lived and worked in the same Manhattan neighborhood where the Patz family lives, the source said.
Investigators have looked at the man before in connection with the case, according to the second source, and his information is being treated very cautiously.
Renewed attention over the Patz disappearance sprung up last month when investigators scoured Miller's SoHo basement, where Etan had been seen a day before he went missing, but it produced no obvious clues.
Hernandez's name "came up more than once while interviewing others recently," said a law enforcement source, who added that authorities had been familiar with him years ago.
The person whom Hernandez had allegedly confided in contacted authorities months ago after news coverage about the renewed search, which -- in part -- prompted investigators to question Hernandez.
A spokeswoman for the Manhattan district attorney's office, which reopened the case in 2010, declined to comment on the recent development.
New York Mayor Michael Bloomberg added that there's "still a lot more investigating to do."
"To his credit, District Attorney Cy Vance reopened (the investigation) in hopes not only of bringing justice, but also offering some closure to Etan's parents," the mayor told reporters Thursday. "And as a father, I just can not imagine what they've gone through."
Etan went missing on May 25, 1979, a block from his home in the Manhattan neighborhood of SoHo. It was the first time he had walked to his school bus stop by himself.
His mother, Julie, learned after her son failed to return home from school that he hadn't been in classes that day. After calling the school and Etan's friends, she called police.
Patz investigation a 33-year roller coaster ride
The boy was officially declared dead in 2001 as part of a lawsuit filed by his family against a drifter, Jose Antonio Ramos, a convicted child molester acquainted with Etan's baby sitter.
A judge found Ramos responsible for the boy's death and ordered him to pay the family $2 million -- money the Patz family has never received.
Though Ramos was considered a key focus of the investigation for years, he has never been charged in the case. He is serving a 20-year prison sentence in Pennsylvania for molesting another boy and is set to be released this year.
A source has previously said investigators wanted to expand the pool of possible suspects beyond Ramos.
Parents Stan and Julie Patz still live in their SoHo home and have not commented on the new developments.
Cohen, author of "After Etan: The Missing Child Case That Held America Captive," told CNN earlier that "the family's been living through this for 33 years. They've had many moments like this. They've learned how to deal with it."
Missing child case 'awakened America'
Just weeks after Etan disappeared, an attacker abducted the first of more than 20 children to be kidnapped and killed in Atlanta. A suspect in that case was arrested two years later.
In 1981, the abduction and slaying of 6-year-old Adam Walsh from a Florida shopping mall also made national headlines.
In 1984, Congress passed the Missing Children's Assistance Act, which led to the creation of the National Center for Missing & Exploited Children.
President Ronald Reagan named May 25, the day Etan went missing, as National Missing Children's Day.