A police officer for the Massachusetts Institute of Technology was shot to death on Thursday night at the school's Cambridge campus, touching off a manhunt for a suspect or suspects in a community on edge just days after the Boston Marathon bombing.
MIT police were sweeping the campus early on Friday, according to a campus alert. Massachusetts State Police and Cambridge police said they were assisting in the investigation.
David Procopio, a spokesman for the Massachusetts State Police, said the motive for the shooting was not known and the investigation would be led by the Middlesex County District Attorney's Office after the death of the officer.
The shooting in Cambridge occurred as nerves were on edge in neighbouring Boston, where two bombs exploded on Monday at the finish line of the city's famed marathon, killing three people and wounding 176.
Procopio said that while he did not believe the shooting was connected to the Boston Marathon bombing, "I can't say that with 100 percent certainty at this time."
State Police were assisting in the search for a suspects, Procopio said in a statement.
FBI Boston Special Agent Greg Comcowich said the office was referring questions about the shooting to Cambridge and MIT police. "I can tell you that we are aware of it however."
The shots on Thursday night were reported near Building 32, MIT said in an emergency statement warning students to "stay indoors and away from the area."
MIT police representatives could not be reached immediately for comment.
Our top photos from the last 24 hours.