WATERTOWN, Massachusetts (AP) – Two suspects in the Boston Marathon bombing – identified to The Associated Press as coming from a Russian region near Chechnya – killed an MIT police officer, injured a transit officer in a firefight and threw explosive devices at police during their getaway attempt in a long night of violence that left one of them dead and another still at large Friday, authorities said.

A law enforcement intelligence bulletin obtained by the AP identified the surviving bomb suspect as Dzhokhar A. Tsarnaev, 19, of Cambridge, Massachusetts.

Two law enforcement officials told AP that Tsarnaev and the other suspect who was not immediately identified have been living legally in the U.S. for at least one year.

Russia's North Caucasus region has been plagued by an Islamic insurgency stemming from separatist wars in Chechnya.