BOSTON -- A Boston University medical student with no criminal record was arrested Monday and charged with being the 'Craigslist Killer,' the man who attacked women who advertised on the Web site to arrange meetings for erotic services.

Philip Markoff, 22, of Quincy, Mass., was charged by Boston police with last week's slaying of JuLissa Brisman, 26, of New York.

Brisman had advertised her massage services on the site. She was killed at the Copley Marriott hotel while resisting a robbery attempt, police believe.

Markoff was also charged with an earlier attack on a prostitute at another hotel.

"He's a predator," said Suffolk County District Attorney Daniel Conley.

Markoff remains a suspect in the attack on a woman at a hotel in Warwick, R.I. The suspect was captured on surveillance photos at all three crime scenes, police said. In several photos, he appears unconcerned as he typed on his BlackBerry.

Police said that they believe these may not have been Markoff's first attacks. Police want to hear from "those out there who may have been a victim at the hands of Philip Markoff, especially those who have used Craigslist," Conley said.

"If you were robbed after placing an ad on Craigslist, we urge you to contact the Boston Police Department," he said.

All the women attacked advertised services on the site and similar plastic restraints were used in all three attacks.

On Thursday night, a Las Vegas woman was bound and held at gunpoint at the Holiday Inn Express hotel in Warwick by a man who answered her Craigslist ad. Her assailant fled when the woman's husband returned to the room.

In surveillance photos released Monday, a white man can be seen walking into the lobby of the hotel and walking up the stairs.

The break in the case may have come from the account of that 26-year-old exotic dancer who was offering lap dances for money at the hotel through her Craigslist posting.

She described to police the striking similarity between her attacker and the man wanted for the Boston attacks. She described her attacker as about 6 feet 3 inches tall with blond hair.

On April 10, a 29-year-old prostitute from Las Vegas was robbed at the Westin Hotel in Boston. She was tied with a plastic cord and robbed of a debit card and $800 cash.

Boston police said investigators had followed up on more than 150 tips received since surveillance photos of the Boston hotels were released last week.

"They followed high-tech leads and they used old-fashioned shoe leather. They connected computer IP addresses to physical locations," Conley said.

Police Commissioner Edward Davis said his detectives had Markoff under surveillance "for days" before making the arrest.

Markoff was arrested after being pulled over on Interstate 95 in Walpole, Mass., Monday afternoon. Police said he did not resist arrest.

Brisman was a model for Near Ear, and was featured as the "Cell Phone Girl" in a video produced by the New York company, according to the company's Web site. Brisman also did some acting and model roles for Spike TV, the Web site said.

Brisman's friends said they didn't know she had advertised massage services online.

Matthew Terhune, 34, a photographer from New York City, said Brisman told him she had been paid $1,000 to fly out to private parties in Chicago and walk around in a bikini or topless. "But I don't think it went beyond that," Terhune said. "They were just parties where guys wanted to see hot girls."

Boston University said Markoff had been suspended from its medical school. He faced arraignment Tuesday morning in Boston Municipal Court.