The police are trying to figure out a possible motive for the accused Craigslist killer Philip Markoff’s assaults on prostitutes and escorts in Boston, including murdered model Julissa Brisman.

According to sources, Markoff was a known gambler and investigators are trying to find if money issues related to high stakes gambling may have led to his sudden violent spree. Markoff is accused in the murder case of Manhattan model Julissa Brisman, 26, who offered professional masseuse services and met him at the Marriott Copley Place hotel. According to police sources, Brisman was giving sensual massages and met her killer through a Carigslist ad she had posted. She was handcuffed with plastic zip-tie binds and shot several times.

Markoff is being held without bail and was to post $250,000 for robbing a prostitute on April 10. He allegedly flung her against the door and then shut her mouth with duct tape. According to the police, a semi automatic gun and ammunition and several “items used to bind” victims were found in Markoff’s apartment at Quincy during a search last night. An IP address that showed his internet provider led to the police to the Quincy apartment where Markoff stays and they conducted the search to find the aforementioned items.

Markoff was seen on the surveillance tapes at the hotel as coming out calmly from the hotel and walking away nonchalantly. Later the bullet riddled body of Manhattan model and aspiring actress Julissa Brisman was found in the posh hotel room. Plastic handcuffs used on the victim linked the assault with two previous assaults in the same week and the police were able to track down Markoff through the handcuffs.