New York (CNN) -- Pedro Hernandez, a former Manhattan stock clerk who once lived in the same neighborhood as Etan Patz, was arrested Thursday in connection with his death, more than three decades after the 6-year-old went missing.
A then-19-year-old Hernandez allegedly lured Patz to a store with the promise of a soda, choked him in the basement and then disposed of the body using a plastic bag, placing it in the trash about a block and a half away, Police Commissioner Ray Kelly told reporters.
"Detectives believe in the credibility of the statement," Kelly said, referring to the man's earlier confession. Authorities were alerted to the suspect by a tip.
Hernandez, who had been working in construction until an injury sidelined him, is expected to be charged with second-degree murder, Kelly said. The suspect is expected to make an initial appearance in court Friday, with the district attorney's office formally filing paperwork.
He has no prior criminal record and is the father of a teenage girl, Kelly said.
Etan's disappearance exactly 33 years ago on 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.
According to police, in the years following Etan's disappearance, Hernandez told a family member and others that he had "done a bad thing" and killed a child in New York. He voluntarily left New Jersey on Wednesday night with detectives to travel to Manhattan and the building, currently an optical business.
Kelly described the suspect as remorseful. "The detectives thought it was a feeling of relief on his part."
He told reporters that other employees of the store were interviewed after Etan disappeared, but not Hernandez. "I can't tell you why," said Kelly, indicating the case apparently was a crime of opportunity.
The commissioner said it is unlikely police will find Etan's remains.
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.
The carpenter, Othniel Miller, 75, had 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."
But a separate law enforcement source said Thursday that Hernandez's claims were being treated with "a healthy dose of skepticism." Investigators have not uncovered any forensic evidence linking Hernandez to the case, Kelly added.
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.
Renewed attention over the Patz case sprung up last month when investigators scoured Miller's SoHo basement, where Etan had been seen a day before he went missing.
But their search produced no apparent clues.
The tipster contacted authorities months ago after news coverage of their renewed search. That contact, at least 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 that he had walked to his school bus stop by himself.
His mother, Julie, learned after her son failed to return home that he hadn't been in classes that day. After calling the school and Etan's friends, she then called police.
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 babysitter.
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. Police said Thursday that Stan Patz was a little surprised and overwhelmed by Thursday's 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."
Thursday evening, Cohen told CNN's "Piers Morgan Night" she had not heard of Hernandez before the arrest. The Patz family, she said, won't be making any quick judgments on this case.
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 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.
CNN's Ross Levitt contributed to this report.