That man was not arrested, but 102 other people were during the 12 day operation.
Police say undercover officers posed as prostitutes, leading to the arrests of 76 men. Authorities also arrested 26 women on charges related to prostitution.
"We're out there every day, but to round up 102 people is something that surprised me," said Lt. Charles Green of the Philadelphia Police.
One man, Ismael Lopez, was arrested twice during the operation, police said. Investigators went on to say he was offering heroin in exchange for sex, and was said to be carrying a gun during the incidents.
Meanwhile, the man police were originally looking for remains at large.
In four unsolved cases, the women were raped and brutally beaten, one of them requiring facial reconstruction surgery.
The suspect is described as a black man in his late 20's to mid 30's. He stands about six feet tall, weighing about 230 pounds. He had short-cropped hair with a mustache, and a light beard or goatee. He wore eyeglasses in one incident.
Anyone with information on his whereabouts is asked to contact police.
Given the pattern and the number of arrests during the sting operation, police now believe the man is not alone.
The prostitutes out there know about the danger, but say they still have to work.
"Yeah, it's scary. You don't know who's who," one woman said. "But, people need the money."
"I have no choice. It's survival for me," another woman said.