Arrest Linked To Gun Used After Boston Bombings

BOSTON — It has been one of the lingering questions since the dramatic manhunt that gripped the Boston area in the days after the marathon bombings: Where did the suspects get the gun that authorities say they used to kill a university police officer?Answers may come soon with the arrest Tuesday of a man that people with knowledge of the investigation say supplied his friend Dzhokhar Tsarnaev with the weapon.Stephen Silva made an initial appearance in federal court on charges related to heroin trafficking and possession of a handgun with an obliterated serial number.