Police are asking Kensington residents to keep in mind that the man who has killed three women in the neighborhood may look nothing like the composite sketch that has been plastered on street posts and in stations along SEPTA's Frankford El line.

Though the man pictured in the sketch is a suspect in nonfatal attacks on three women in the neighborhood in recent months, he might have no connection to the serial killer preying on women there.

Investigators are still analyzing DNA evidence found last week at the site of Casey Mahoney's slaying. Depending on the sample, the genetic material could help determine the killer's race.

Women involved with drugs or prostitution in Kensington should take extreme caution when dealing with men they don't know, Philadelphia Police Lt. Raymond Evers said.

"These women need to be careful," he said. "Some might think it's safe if they don't accept a 'date' with a young black man. Maybe they think an older white guy is fine. But he could be the guy who's doing the stranglings."

Police have flooded Kensington in recent weeks, using undercover and uniformed officers to arrest people involved in prostitution in an effort to find a suspect in the killings. Authorities also are asking women in the area not to walk alone and to avoid high-risk behavior, such as following strange men to deserted places.

A $37,000 reward was posted this week for information leading to the arrest and conviction of the man responsible for the slayings. Of that, $7,000 can be awarded to anyone who provides information leading solely to an arrest, no conviction required.

DNA evidence has determined that the three women strangled in Kensington since Nov. 3 were killed by the same man. In addition to the DNA, the slayings share circumstantial similarities: The women were white, between the ages of 21 and 35, and were all involved in drugs or prostitution. Each was found nude from the waist down, showing signs of sexual assault. Two of the women were found posed in the same position.

Investigators have no conclusive evidence linking the three nonfatal attacks to the slayings. But like the slain women, the surviving victims are white. They were working as prostitutes. At least two were choked to the point of unconsciousness, and they told police they were sexually assaulted. The attacks took place near or at the places where the slaying victims were found.

"These things do match up," Evers said. "There's a lot of comparisons. But we can't say with 100 percent certainty that we're talking about the same guy."

The women who survived the assaults have all described their attacker similarly, and police used those descriptions to develop the composite sketch.

The man in the sketch is slender and in his 20s. He stands between 5-foot-7 and 5-foot-10. The first two victims, who were attacked in October, said he had a goatee and a mark on his cheek. A woman who was attacked weeks later told police there was no goatee or mark, and she said he had sideburns. Two women described him as soft-spoken; one said he had carried a white iPod and called himself Anthony.

A surveillance camera near the site of a Dec. 6 nonfatal attack also captured the image of a man who appears to resemble the composite sketch.

Anyone with information is asked to call 911 or 215-686-8477.