During an interview with Detective Matt Rowles, Gonce said he killed a man and woman in his Secane apartment in February 2012, used a hacksaw to cut apart their bodies, and then used the pimp's Cadillac to drive the packaged remains to Indian Rock Park in Springfield Township, Chitwood said.
Gonce led police to the site in the park and pointed to the area where he said the body parts could be found, Chitwood said. Gonce was then sent back to prison.
A front-end loader was brought to the park and was digging until around 9 p.m., when the search was called off for the night. The digging will resume Saturday morning, Chitwood said.
"We have not found anything," he said.
There are no missing-persons reports connected to the individuals, whom Chitwood did not name.
Gonce said "he felt he got ripped off" by the pimp and prostitute, so he used a knife to cut their throats and stab them, Chitwood said.
Gonce, facing a possible death penalty in the double slaying, said he wanted to publicly confess and provide closure to family members of the man and woman, Chitwood said.
He was on the run in the double-homicide case when he persuaded a cousin to let him hide at her Maryland home. Four days later, police said, he raped his cousin's 13-year-old daughter. That led to his arrest.