A 48-year-old man and a 38-year-old woman were shot to death in the Lemon Hill section of Fairmount Park, Philadelphia police said.
Their bodies were found at 11 p.m. Thursday on the 3800 block of Mount Pleasant Drive – near the historic Mount Pleasant Mansion, which has been closed to the public since last year.
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Police said the man was shot in the head; the woman had gunshot wounds to her chest and head. Chief Inspector Scott Small told 6ABC that three shell casings were found near the bodies.
"At this point, it appears they were both shot (and) killed execution-style, not only because they're lying next to each other," Small told the station. He said evidence suggests at least three shots were "fired from a semiautomatic handgun or handguns."
The people killed were identified Friday afternoon as Thurston Cooper, 49, and Krystina Chambers, 38, both of Philadelphia.
There are no known suspects or motives. Police said they planned to examine surveillance footage from Mount Pleasant Mansion as part of the investigation.
A $40,000 reward is being offered for information leading to an arrest and conviction, police said. Anyone with information can call the police department's homicide unit at (215) 686-3334.
PhillyVoice staff writer Michael Tanenbaum contributed reporting to this story.