A man charged with having the gun prosecutors believe the Boston Marathon bombing suspects used to kill an MIT police officer has pleaded guilty to gun possession and drug charges.
Stephen Silva changed his plea to guilty Friday in federal court. He initially pleaded innocent after he was charged in July with possession of a handgun with an obliterated serial number and heroin trafficking.
The 21-year-old Silva was a friend of bombing suspect Dzhokhar Tsarnaev.
Silva's lawyer has confirmed the handgun is the same gun authorities believe Tsarnaev and his older brother used to kill Officer Sean Collier while a massive manhunt was underway for the Tsarnaevs.
Three people were killed and more than 260 were injured in the 2013 bombing. Tsarnaev's trial is to begin Jan. 5.