Police in both Boston and Rhode Island have said they believe the attacks may have been carried out by the same person.
On Monday, investigators released a clear photograph of the suspect taken during the most recent attack in Warwick. A series of images show the suspect inside the Holiday Inn Express Hotel last Thursday evening, the scene of an attempted robbery of a woman.
The man seen in the pictures taken in the hotel closely resembles the man seen in a surveillance camera photo that was released after Brisman was found dead just days earlier.
Detectives have also a match among plastic zip-tie cuffs used to bind all three women. Two law enforcement sources told ABC News that the plastic restraints were being investigated after they were used to bind the hands of the victims.
"Detectives are aggressively pursuing a number of promising leads," Boston Police Department spokeswoman Elaine Driscoll told ABC News earlier today, refusing to comment on the plastic cuffs.
The man captured on a series of surveillance cameras in Boston's upscale Back Bay was a 20-something, clean-cut blond man who was seen leaving a luxury hotel where police said Brisman, a masseuse, was shot and killed just moments before in her room.
Brisman's death is the second in a series of crimes against women who police say advertised on Craigslist.
After the arrest, Craigslist CEO Jim Buckmaster issued a statement, saying, "We are very pleased to hear that the person alleged to have committed these crimes has been arrested, and we will continue to provide law enforcement agencies with any assistance necessary to prosecution of the case."
ABC News' Scott Michels contributed reporting to this story.