Three recent sexual assaults of a young woman and two teenagers in Frankford have police investigating whether there is a serial rapist in the area.

The victims gave similar - though not exact - assailant descriptions that prompted police to fast-track DNA evidence, but it will still take several weeks for results, Chief Inspector William Colarulo of Special Investigations said yesterday.

Police are asking residents to watch for suspicious activity and warning women to take safety precautions.

The victims were alone when they were attacked. Police said it appears the assailant or assailants are familiar with the area.

"It may or may not be the same suspect responsible for all three of the sexual assaults," Colarulo said. But because of the similarities, "We felt it important to notify the public, through the media, of these sexual assaults."

In addition to DNA evidence, police obtained fingerprints. Lt. Thomas McDevitt of the Special Victims Unit said detectives are searching databases of recently released criminals as well as known sex offenders for matches.

The first assault happened at 1 a.m. June 11 in the 1100 block of Adams Avenue, where a 16-year-old girl told police she was abducted near a CVS drug store and pulled into a back alley. The assailant threatened to cut her throat as he raped her, police said.

At 6 a.m. Tuesday in the 1600 block of Wakeling Street, a 21-year-old woman was walking to her car, parked near her home, when she was confronted by a man armed with a small, silver revolver.

The man forced her into her car, put the gun to her head, sexually assaulted her and stole her purse.

At 10 p.m. Thursday in the 4700 block of Darrah Street, a 16-year-old girl reported, a man followed her when she got off the Frankford El at Margaret and Oxford Streets.

The attacker confronted her with a small, silver handgun. He stole a small amount of money from her and sexually assaulted her with the gun pointed to her stomach.

The suspect is described as a black male with a dark complexion, in his late teens or early 20s. He is about 6 feet tall, weighing about 170 pounds with a medium build. He was wearing dark denim jeans.

Two of the victims said the attacker was wearing a hooded sweatshirt with the hood pulled up. The second victim said the assailant was wearing a red hoodie with a green or gray emblem in front. The third victim said the assailant wore a gray hoodie with a red emblem on the chest.

Anyone with information is asked to call the Special Victim's Unit at 215-685-3251.

Contact staff writer Barbara Boyer at 215-854-2641 or bboyer@phillynews.com.