Police in Kensington arrested 102 people over the last two weeks during a prostitution sting aimed at catching a violent rape suspect, authorities announced yesterday, but failed to find the one they were looking for.

The 12-day operation, which targeted johns and involved undercover female officers posing as prostitutes, was an effort to corner the man or men responsible for the rapes and beatings of several prostitutes in recent months.

But the sting failed to turn up anyone police could charge in those attacks, even after taking DNA samples from those fitting the description of the prostitutes' attacker.

Officers said yesterday that an increased police presence would remain on and around Kensington Avenue, where four women were picked up and attacked.

"We wanted to try to catch this guy in the act," said Lt. Charles Green of the city's vice squad. "And we wanted to act as a deterrent. We wanted to send the message that if you're going to come down to Kensington Avenue or any other area of Philadelphia, to engage in an illegal activity, you may be doing so with an undercover officer."

Police arrested 76 men on charges of solicitation and other offenses, and 26 women who are accused of prostitution.

One man, Ismael Lopez, was arrested twice during the sting. The first time, he offered heroin to an undercover officer in exchange for sex, police said, and was found to be carrying a handgun.

Another man arrested was carrying a 10-inch butcher knife, Green said.

"It just goes to show you how dangerous it is down there," he said. "These girls subject themselves to a lot of danger, take a lot of risks."

The level of violence in the Kensington attacks was the driving force behind the decision to flood the area with police, Green said yesterday.

At least four women have been attacked since October by a man who encountered them walking near Kensington Avenue at night. In each case, the attacker beat the victim with his fists, causing facial fractures and in one case breaking a victim's jaw. One woman was so badly injured, police have been unable to interview her.

Police are not sure whether the same person is responsible for all the attacks, and have said there are differences between the cases.

A composite sketch of the man has been released, although only one of the victims could describe her attacker's race. She said he was black, in his 20s or 30s, 5 feet, 10 inches to 6 feet, 2 inches, and about 230 pounds. He had a beard or goatee. She said he wore glasses, but other victims said he did not.

Anyone with information is being asked to call police.

Police believe the assaults, which occurred in vacant lots, alleys, a cemetery, and near train tracks, are not connected to four assaults they linked to a Northeast Philadelphia man last month.

During the investigation into the string of assaults in Kensington, police uncovered another series of four rapes that they believe were committed by Kevin Maxwell.

Maxwell, 25, of the 3500 block of Woodhaven Road, has denied raping the women but admitted paying them for sex. He faces charges in four attacks.