Police identified the 54-year-old man who was shot as Robert Jones.
The shooting happened around 11:30 p.m. at the intersection of Holme Avenue and Willits Road in Northeast Philadelphia.
Police say Detective Christopher Sweeney and Jones had stopped their vehicles on the roadway.
Jones got out of his vehicle and approached the detective's personally owned vehicle on foot, according to police.
Sweeney, who police say was seated in the driver's seat, fired his personally-owned gun at Jones multiple times, investigators said.
Jones was taken to Jefferson-Torresdale Hospital by paramedics, where he was later pronounced dead.
Officials earlier said the call came in as an attempted carjacking. In an update released Friday afternoon, police officials said the circumstances of the shooting remain under investigation.
Police have not yet said whether the suspect was armed.
At the scene, the Sweeney's car could be seen with a shattered driver's side window.
The Action Cam was there as Water Department crews used machinery to dig in the sewer under the guidance of Philadelphia police detectives. It's not known what they were looking for or if anything was found.
Police say Sweeney, 43, is assigned to the Homicide Unit and is a 14-year veteran of the force.
He was placed on administrative status pending the outcome of the investigation.
Anyone with information is urged to contact the Philadelphia Police Department at 215-686-TIPS (8477).
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