BOSTON -- Forensic tests have placed Philip Markoff, the man accused of being the “Craigslist Killer,” at the scene of one of the crimes of which he is accused, the Boston Globe reported Thursday night.

Fingerprints found on the plastic restraints and duct tape left at one of the crime scenes matched Markoff's fingerprints, the Globe reported.

The newspaper did not say whether the fingerprints were found at the Marriott hotel where JuLissa Brisman, 26, of New York was killed or at the Westin hotel where a prostitute from Las Vegas was robbed and attacked.

The gun found in Markoff's Quincy apartment is believed to be the one used to kill Brisman, NewsCenter 5 previously reported. The Globe reported there has been a preliminary match between the semi-automatic handgun found in the apartment and the murder weapon.

Markoff was placed on suicide watch Thursday after correction officers found shoelace marks on his neck, according to law enforcement sources. Those who have seen him since his arrest describe him as "catatonic," NewsCenter 5's Sean Kelly reported

Markoff has been moved from the general population at Boston’s Nashua Street Jail and is under constant watch in a segregated unit.

Markoff’s lawyer, John Salsberg, would neither confirm nor deny that Markoff had been placed on suicide watch Thursday, but he said that he was concerned about Markoff because he had been having a “tough time” transitioning to life as an inmate. Salsberg said that Markoff’s family remains supportive and is also concerned about his safety.

“It's difficult for anybody to make the transition from a life of freedom to being incarcerated or detained, particularly the first few days,” said Salsberg. “However, I have a tremendous amount of confidence that the Sheriff's Department of Suffolk County is going to make sure that he’s well taken care of and looked after.”

Markoff, 23, of Quincy, was charged with robbery, kidnapping and murder Tuesday in connection with the shooting death of Brisman, a massage therapist who advertised services on Craigslist. He was ordered held without bail pending his next court appearance in May.

Brisman was found shot to death in her Marriott Copley Square hotel room on April 14. Markoff was also charged in the case of a Las Vegas prostitute who was bound and robbed in the Westin Hotel a few days earlier.

Earlier on Thursday, the father of Markoff's fiancee, Megan McAllister, said that his daughter is still confident in the BU medical student. James McAllister told reporters that Megan McAllister has been holding up "as well as expected" in light of the allegations against Markoff.

Markoff is also suspected in an attempted robbery in Warwick, R.I., of a woman who had posted a Craiglist ad as a stripper. She 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.

Investigators are looking into whether Markoff had developed a gambling habit.

"As we explore various motives for the robberies, gambling is certainly a motive that we will look at," Suffolk County District Attorney Dan Conley said Tuesday.

Markoff opened a line of credit at Connecticut's Foxwoods Casino in 2008. His visits there increased in March and April of 2009, ABC News reported.

Two days after the attack on the prostitute in Westin Hotel that netted $800, Markoff was at the casino on April 12. Two days later, on April 14, Brisman was killed at the Marriott Hotel. Two days after that, Markoff was back at Foxwoods, collecting winnings of $5,300.

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