Police, now with a DNA sample, are asking for the public's help to find the man they said raped an 18-year-old girl early one morning last summer on her way to work in the Northeast.

"He's a dangerous male," said Capt. John Darby of the Special Victims Unit. "This is just a particularly egregious assault."

The woman was walking to a bus stop about 6 a.m. Aug. 28 near C Street and Roosevelt Boulevard when she was grabbed from behind, dragged into an alley, and sexually assaulted, Darby said.

City police were notified recently by state police that a DNA sample from the attack matched a man recently incarcerated.

Po lice issued a warrant for Lionel Rivera, 23, whose last known address was the 300 block of Louden Street, close to the crime scene. Darby said investigators believe Rivera is still in the area.

Anyone with information about Rivera is being asked to call police at 215-686-8477 (TIPS). Callers may remain anonymous.

It was the second time this week that police charged a rape suspect after evidence of the crime scene matched a DNA profile in the state's database.

On Thursday, police charged Jose Quinones, 39, of the 2400 block of Fifth Street, with rape after state authorities notified city police his DNA matched that taken from a crime scene in December 2002.

In that case, a 28-year-old woman reported that she was sleeping in bed with her infant when a man broke into into her East Madison Street home and sexually assaulted her.

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