(NewsNation) — More than six decades after the “boy in the box” was found in Philadelphia, police have identified him as Joseph Augustus Zarelli.

One of America’s oldest unsolved cases, the boy in the box was found in 1957 and police have continued to search for his identity in the decades since.

Zarelli’s naked, badly bruised body was found on Feb. 25, 1957, in a wooded area of Philadelphia’s Fox Chase neighborhood. The boy, who was believed to be between 4 and 6 years old, had been wrapped in a blanket and placed inside a large JCPenney bassinet box. Police say he was malnourished. He’d been beaten to death.

His photo was put on a poster and plastered all over the city as police worked to identify him and catch his killer.

Detectives investigated rumors he was a Hungarian refugee, a kidnapped boy from Long Island and other missing children but none of the leads panned out.

Police say DNA analysis helped them finally identify the boy.. Zarelli’s remains were exhumed in 1998 and again in 2019 to obtain material for DNA analysis.

Zarelli was born on Jan. 13, 1953 and police used forensic genealogy to identify living relatives and learn his name. Both birth parents are deceased, but out of respect for the living siblings on both sides, police are not releasing their names.

The case captured the attention of many and the Vidocq Society, a group of volunteer investigators and forensics experts, who also worked on the case.

Police said they have suspicions about who killed Zarelli, but they are not releasing that information as the investigation is still considered an active homicide case.

Capt. Joseph Smith, with the homicide division, acknowledged the investigation will be an uphill battle given the amount of time that has passed since Zarelli was discovered.

A $20,000 reward is being offered for information.

The Associated Press contributed to this report.