After investigating, however, police are skeptical.
"Right now he has no credibility," Superintendent Michael Chitwood said.
On Friday, Gonce relayed a message through prison officials to Upper Darby police that he wanted to meet.
Over a mushroom pizza, soda, and cigarettes, Gonce gave Upper Darby detectives a 16-page handwritten statement.
Gonce claimed that in February 2012 he confronted the pair in the parking lot of the New Orleans Park Apartments in the Secane section of town and said he was unhappy with the service the prostitute provided for $250.
According to Gonce's statement, he brought the two back to his unit, forced them to strip in the bathtub, where he stabbed them, used a hacksaw to cut apart their bodies, wrapped their remains, and used the pimp's Cadillac to drive the bodies to the wooded park, Chitwood said.
Gonce told police he dumped the car in Camden and called a friend, whom he would only identify by the initial "J," to pick him up, Chitwood said.
"When you look at his statement, it is very convincing," he said.
But after two days of digging to no avail, the statement's credibility appears to have evaporated, he said.
Gonce, who is now back in a Philadelphia jail, told detectives he wanted to clear his conscience, said Chitwood, and police had an obligation to check out his statement.
"If you don't follow up, you are remiss," he said.
Police brought Gonce to the park, where he pointed out the area where he said he had buried the bodies in a four-foot grave. A K-9 cadaver dog got a "semi-hit" in the area, Chitwood said.
After an attempt at shoveling the dirt, police called for a front-end loader.
That is when the story began to fall apart, he said.
"If we couldn't dig it up in August, he couldn't dig it up in February," when the ground is much harder, Chitwood said.
Two days of digging yielded nothing, he said.
Police are still investigating. They are looking at missing-persons reports, Chitwood said.
"Who knows what he is trying to do?" Chitwood said.
According to charges pending in Philadelphia, Gonce killed Rohan Bennett, 13, and Christopher Malcolm, 17, on July 24, 2012. Police have said the boys' parents were higher-level drug dealers. Malcolm, who was shot once in the chest, had three previous drug arrests. Police said Bennett, a straight-A student who had just finished middle school, was an innocent bystander.
Gonce is also charged with raping a 13-year-old second cousin in Maryland, Chitwood said.
"He is," he said, "a cold-blooded killer."