Nearly 66 years after the battered body of a young boy was found stuffed inside a cardboard box, Philadelphia police are set to reveal the identity of the victim in the city’s most notorious cold case.

Police say detective work and DNA analysis helped them learn the name of a youngster who’d been known to generations of Philadelphians as the “Boy in the Box.” Authorities are set to publicly release the victim’s name on Thursday.

The case is Philadelphia’s oldest unsolved homicide.

The child’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.

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

Detectives pursued and discarded thousands of leads — that he was a Hungarian refugee, a boy who’d been kidnapped outside a Long Island supermarket in 1955, a variety of other missing children. They investigated a pair of traveling carnival workers and a family who operated a nearby foster home, but ruled them out as suspects.

An Ohio woman claimed her mother bought the boy from his birth parents in 1954, kept him in the basement of their suburban Philadelphia home, and killed him in a fit of rage. Authorities found her credible but couldn’t corroborate her story — another dead end.

All the while, the boy’s missing identity gnawed at police officials, generations of whom took up the case.

Set to appear Thursday are Police Commissioner Danielle Outlaw along with other law enforcement officials, as well as a genetic genealogist and the co-founder of a group of professional sleuths, called the Vidocq Society, that took up the Boy in the Box case a quarter-century ago.