Everything in the gruesome double murder that has shaken Philadelphia in recent days points to a passionate motive, police said.
Shakoor Arline and Lisa Smith, both 25, were having sex in the back of an SUV when they died of multiple gunshot wounds to the head early on Friday.
There was no evidence to indicate a robbery, police said Tuesday.
Both victims were also dating other people.
The couple were discovered in their car Friday afternoon in Philadelphia's Fairmount Park, the Associated Press reported.
Police believe "somebody [who] knew they were in the park and obviously had an issue with that" walked over, opened the rear door of the car, and shot nine times."
"You've got nine shots fired, all of them head shots to both of the victims,"James Clark, a homicide captain with the Philadelphia police, told the AP. "It appears to be very much a crime of passion."
Police have not arrested anyone, the AP reported, but they have spoken to a woman and are looking for a man.