Agents from an FBI behavioral analysis unit in Quantico, Va., will join the hunt for the man responsible for strangling at least two women in Kensington, an agency spokesman said.
The agents will create a profile of the attacker in the cases that are believed linked, said FBI spokesman J.J. Klaver. The profile will assist Philadelphia detectives in their investigation of the sexual predator.
"Quantico will get involved," Klaver said, referring to the unit at the FBI Academy.
Klaver said the FBI would provide forensic assistance to the investigation, and he emphasized that the Philadelphia Police Department would remain the lead law enforcement agency on the case.
So far, DNA has linked the murders of two women in Kensington.
Last week, police also found the body of Allison Edwards, 22, in nearby Juniata Park. Edwards, too, was strangled, but police were still investigating whether her death was connected to the earlier stranglings.
Several other women have reported being sexual assaulted and choked by their assailant, and one provided details for a police sketch. It is not known for certain if the man in the sketch is the same as the killer in the DNA-linked slayings.
The two slain women linked through DNA are Elaine Goldberg, 21, whose body was found Nov. 3, and Nicole Piacentini, 35, whose body was found Nov. 13.
On Tuesday, police said another woman had come forward to report a sexual assault in Kensington, on Allegheny Avenue near Frankford Avenue, shortly before midnight Monday.
The woman got inside the man's truck, and then he physically and sexually assaulted her, police said. The woman told police her attacker was a Hispanic man in his 30s or 40s with a medium build and a goatee. The description is similar to that of a man who is wanted in the attacks on three other women. None of the other women has reported that the man had a car.
The surviving victims have described their assailant as a slender, light-skinned black or Latino man in his 20s who stands between 5-foot-6 and 5-foot-10.
The composite sketch released by police last month showed a man with a mark on his cheek and a goatee. A modified composite sketch released by police following Monday's attack depicted the same man, without a goatee and with sideburns.
Anyone with information is being asked to call the Special Victims Unit at 215-685-3251, or to dial 911.