Investigators are looking into gambling as the possible motivation for a Boston medical student accused of targeting women who advertised erotic services on Craigslist, luring them into hotels to rob them and killing one woman who fought back.

Philip Markoff is accused in the death of Julissa Brisman, a masseuse who was found dead April 14 in a Boston hotel after being bashed in the head and shot three times. He's also suspected of robbing and tying up another, and police have said there could be more victims.

A Connecticut casino has confirmed it is cooperating with authorities investigating Markoff's gambling habits.

Markoff was arrested on Monday on Interstate 95 in Massachusetts as he and his fiancee drove to Foxwoods Resort Casino.

"We do not release information publicly concerning individual patrons; however, we are aware of this situation and are cooperating with the appropriate law enforcement authorities," the casino and the Mashantucket Pequot Tribal Nation said in a statement.

Suffolk District Attorney Daniel Conley refused to comment directly on reports that Markoff might have been seeking money to pay gambling debts.