The Boston Police Department reports three additional suspects have been arrested in connection with the marathon bombings.

The Boston Globe identifies them as college students, but gives no more details.

Boston police followed that up with a another tweet indicating there is no threat to the public.

Only two suspects were identified in the days immediately after the bombing. Tamerlan Tsarnaev is dead, while Dzhokhar Tsarnaev is in custody.

3:00 p.m. - A backpack with emptied fireworks is at the center of new arrests in the Boston marathon bombing.  Two suspects are charged with obstruction of justice and another is charged with lying to investigators.  They're accused of conspiring to throw away Dzhokhar Tsarnaev's backpack to protect him.