The shoelace marks were viewed as a "suicide attempt," a source said, and he was moved to the "shu unit" -- a segregated unit -- where he was issued a paper gown and was to sleep on a cot without sheets or blankets, just a bare mattress.
Markoff's attorney, John Salsberg, visited the inmate Thursday, but declined to discuss whether Markoff tried to commit suicide.
"I am deeply concerned for Philip's well being and I have complete faith that the sheriff's office will take care of him," Salsberg said.
He added that the transition for any individual from civilian life to prison life is extremely hard and Markoff's experience is no exception.
Police say Markoff killed Brisman April 14 in an upscale Boston hotel and robbed at least one other woman in Boston after binding her with plastic ties.
Markoff's fingerprints were found on the plastic ties used on one of the victims and in the room where Brisman was killed, police sources told ABC News.
A law enforcement source close to the investigation told ABC News that officers recovered a semi-automatic handgun and panties belonging to Brisman in the Quincy, Mass., apartment Markoff shared with his fiancee. The gun and panties were hidden in a copy of the popular medical school textbook "Gray's Anatomy."
The gun found inside Markoff's apartment is a forensic match to casings on bullets used to shoot and kill Brisman, ABC News has learned.
In addition, investigators said the plastic restraining ties used in an attack at a Holiday Inn Express in Warwick, R.I., -- on a woman who had advertised "erotic services" -- exactly match plastic ties found in Markoff's apartment.
In a twist, however, Warwick Police Chief Col. Steve McCartney told ABC News that the woman who was robbed in the Holiday Inn Express was reluctant to cooperate with the investigation.
The developments in the case were disclosed amid a published report Thursday on Markoff's past interaction with a female friend.
Morgan Houston said she had a close call with Markoff, one of her study buddies when the two attended the State University of New York at Albany, after a night of partying four years ago.
"In a doorway, he pushed me up against the wall and tried kissing me," she said in a New York Daily News video. "I was trying to push him away, saying, 'No Phil, get off me.'"
Houston said she wasn't strong enough to push Markoff away, but that a mutual friend came to her aid.
"He had to physically pull him off me," Houston said.
Houston said it was the only time Markoff was aggressive toward her.
As news of the evidence trickles out, a profile is emerging of the man police believe attacked and robbed women he met through Craigslist to pay off his gambling debts.
Police have said Markoff's finacee, Megan McAllister, who has stuck by him and not said much publicly, was accustomed to a lavish lifestyle that may have been financed, at least in part, by the money he got from robbing other women.
The couple's wedding Web site has been taken down.
McAllister's father said his daughter is coping with the help of friends, and that she knew nothing of the alleged crimes.
"She's still confident in Phil," Jim McAllister said. "Other than that, we're saying a lot of prayers."
Markoff's high school yearbook paid homage to his penchant for gambling. As a senior, he wrote, "I bequeath my poker playing skills to Andy Finley so he won't lose his dad's house."