BOSTON -- Eight days after the killing of prosecutor Paul R. McLaughlin, Suffolk District Attorney Ralph C. Martin II yesterday acknowledged that investigators have "no firm suspects," and that the search for the killer will likely be a slow one.
Reflecting the frustration that has enveloped the intense investigation into the slaying of Mr. McLaughlin, Mr. Martin said in an interview that authorities have questioned several people, but that no suspect has emerged.
He also said that the lack of a suspect and the uncertainty over motive have led investigators to examine Mr. McLaughlin's private life.
Mr. McLaughlin, according to colleagues, was a workaholic who spent many evenings devoted to the cases he was handling as an assistant attorney general assigned to the Suffolk district attorney's office to prosecute gang members.
When not working, the 42-year-old was active in Democratic politics in West Roxbury as well as fund-raising for the library in West Roxbury, according to colleagues and friends.
In more routine murder investigations, Mr. Martin said, a list of suspects usually develops quickly as police scour the victim's background, business contacts and professional life. But that has not happened in the McLaughlin case, where, despite an offer of a $40,000 reward, promising tips to police have been in short supply, he said.
"What I'm saying here is we are taking a look at his personal life," Mr. Martin said. "We've been inside his house, and we've talked to friends and colleagues. But that's just part of the overall investigation."
He added that the examination of Mr. McLaughlin's personal life does not mark a change in the basic course of the investigation, which remains premised on the ideas that the assistant attorney general was killed either because of his work or during a bungled armed robbery attempt.
"Now that certainly doesn't mean that it takes precedence over the primary theories, which is that it was either a botched robbery or a something focused directly on Paul because of his work in the office," Mr. Martin said. "Those are still the two primary theories."
Mr. McLaughlin was shot in the head on Sept. 25 as he was entering his car in a parking lot at the Highland commuter rail station in the city's West Roxbury neighborhood. Based on a description given by an eyewitness that day, Boston police are looking for a teen-ager, seen running from the scene.
Police said the youth, originally described as 14 or 15, could be older. Lt. Robert O'Toole, a police department spokesman, said yesterday that police are continuing to look for someone matching that description.