UPDATE: The DA's office reports a suspect is in custody and that investigators have identified the victim - although they are withholding his or her name pending notification of next of kin. Cambridge Police say "this was not a random act," and there is no threat to the public.
Police have sealed off a two-block area around Binney and Sixth - and have evacuated residents.
The Middlesex County District Attorney's office reports on the murder investigation at 225 Binney St.
Preliminary observations reveal that a duffle bag was found this morning which contains human remains.