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A New York City masseuse murdered by the so-called "Craigslist Killer" was found dead in a Boston hotel doorway after she'd been shot three times and bashed in the head.

Julissa Brisman, 26, had advertised her erotic massage services on Craigslist. Police believe she was killed after trying to fight her attacker — who authorities say is med student Philip Markoff.

Brisman's underwear was allegedly found in the suspect's Boston-area apartment and a gun was stuffed into a hollowed-out "Gray's Anatomy" textbook, according to media reports.

The Boston Herald said Markoff hoarded the underwear of two of his victims — Brisman and a 29-year-old Las Vegas woman who survived an armed robbery. Both advertised massage services on Craigslist.

Markoff, 23, also allegedly stashed a gun in a hole carved into his copy of the medical text "Gray's Anatomy," the Herald said.

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"There are various items of all kinds of ilk that we feel are connected to (the) incidents . . . that are subject right now to forensic examination," the newspaper quoted Lt. Detective Robert M. Merner as saying when referring to the "souvenirs" allegedly discovered in Markoff’s Quincy, Mass., apartment.

Markoff is charged with killing Brisman at the Boston Marriott Copley Place hotel on April 14. He also is charged in the robbery of a woman at another Boston hotel four days earlier.

He has pleaded not guilty to the murder, armed robbery and kidnapping charges.

Police haven't publicly confirmed the discovery of the underwear, and the now-suspended Boston University med student hasn't been accused of sexually assaulting either victim. Prosecutors have said he went through the purse of the first woman he's accused of robbing.

Meanwhile, a college friend of Markoff's told the New York Daily News that she once had a scary encounter with the accused attacker after a night out drinking. The two were walking back to their dorms on campus after a fraternity party.

"He pushed me up against the wall and tried kissing me," Morgan Houston, who was in the same pre-med program as Markoff at SUNY Albany, told the News.

She said she protested, but was frightened because her study partner was trying to overpower her.

"No, Phil, get off me, stop kissing me, I'm not interested in you, what are you trying to do?" Houston says she told him, as she tried to break free in the dark. "I couldn't physically get him off of me. Thankfully, he wasn't on top of me, but I couldn't push him away."

Luckily, another male friend who was walking by yanked Markoff away from Houston, the News reported.

"I don't know what would have happened," she told the paper from her family's home in South Carolina. She said she brushed the incident off as the result of too much drinking, and the pair never talked about it again.

A law enforcement official, speaking to the Associated Press on the condition of anonymity because he was not authorized to discuss the case, said Markoff had been placed on suicide watch at the Boston jail he is being held. Multiple media outlets reported what appeared to be shoelace marks were found on his neck.

Markoff's supporters have taken to Facebook to rally around him.

A new Facebook group called "Phil Markoff is Innocent Until Proven Guilty" describes itself as a forum to counteract the media and a culture "that has forgotten that people like Phil are suspects, not killers."

Investigators in the case are looking into gambling as the possible motive for the attacks. The law enforcement official said Markoff was a "frequent visitor" to Foxwoods casino in Connecticut.

Foxwoods Resort Casino, in Mashantucket, Conn., has confirmed it is cooperating with authorities investigating Markoff's gambling habits.

The med student was arrested on Monday on Interstate 95 in Massachusetts as he and his fiancee drove to Foxwoods.

A wake for Brisman was held Wednesday in Manhattan, where her parents live.

The Las Vegas woman was robbed and tied up April 10 at the Westin Copley hotel in Boston. Police have said there could be more victims.

Defense attorney John Salsberg has said Markoff isn't guilty of the charges and "has his family's support."

Markoff's fiancee, Megan McAllister, insists police have the wrong man.

McAllister, who earlier this week told ABC News in an e-mail that Markoff could not hurt a fly, is still standing behind him, her father, James McAllister, told reporters Thursday.

"She's still confident in Phil. Other than that, we're saying a lot of prayers," he said outside his home in Little Silver, N.J.

Suffolk District Attorney Daniel Conley said he believes Markoff's original motive was robbery but he ended up killing Brisman when she fought back.

The first woman Markoff is accused of robbing said she thinks she's alive because she didn't resist.

"I just complied with everything he wanted me to do and I didn't resist him in any way, and I think that's why," she said in an interview with Boston television station WCVB.

Prosecutors have not released her name.

She said she had identified Markoff from the surveillance photos police distributed. He was wearing the same clothing and she recognized his face, she told the station.

The woman said she was able to slip out of the plastic ties she was bound with about a minute after Markoff left and escape. She was robbed of $800 in cash, a debit card and $250 in American Express gift cards, she said.

Markoff also is suspected in an attempted robbery in Warwick, R.I., of a woman who had posted a Craigslist ad as a stripper. The woman was held at gunpoint before her husband entered the hotel room and her attacker fled.

Rhode Island Attorney General Patrick Lynch said in a statement Wednesday that Warwick police have developed "promising information" about the April 16 robbery at the Holiday Inn Express & Suites.

"Although we're encouraged by the progress being made, this is a complex investigation and is going to take more time," Lynch said.

Connecticut Attorney General Richard Blumenthal on Wednesday called on Craigslist to stop what he calls "pimping and prostitution in plain sight."

He asked the site to immediately eliminate photographs in the "erotic services" section, hire staff to screen images and ads that violate the site's terms of service and fine those who violate those terms.

But Craigslist's CEO, Jim Buckmaster, said criminals who use the site are virtually guaranteed to get caught because they leave electronic trails that are easily traced.

"So don't use Craigslist for crime unless you want to go to jail," he said Wednesday in an interview from San Francisco, where the company is based.

Buckmaster said there have been billions of interactions on Craigslist and added "compared to human society as a whole the risks of Craigslist are low, but they're not zero."

Jake Wark, a spokesman for Suffolk County prosecutors, said Boston Police placed an ad in the "erotic services" section of Craigslist. He said police hope the ad will persuade any other women who may have been victims of Markoff to come forward.

The posting does not mention Markoff by name, and Wark said investigators are not sure there are other alleged victims.

Click here for more on this story from the New York Daily News.

Click here for more on this story from the Boston Herald.

The Associated Press contributed to this report.