From the iSteve comments:
Been listening to Boston PD police scanner. Suspects identified as [Deleted] (dead, black hat suspect), [Deleted] (at large, white hat suspect).
I live in Cambridge. I have been following since about 10:30 PM EST, when the MIT shooting kicked off. Heard the explosions in Watertown from Cambridge.
Current situation (4 AM local) is that the police are holding a perimeter around the suspect, and waiting for daylight.
ST would be the missing Brown U. student.
MM sounds like an Italian name to my tin ear, but most of the people on Facebook with that name are Ethiopians. (Something to do with the Italian conquest of Ethiopia in 1936?)
Ethiopia and Kenya are the world's leading marathon rivals. Kenya traditionally dominates the Boston Marathon.