By Elizabeth Barber
BOSTON, Aug 6 (Reuters) - A high school friend of the accused Boston Marathon bomber pleaded not guilty on Wednesday to charges including having owned a gun that prosecutors believe may have been used by suspects in the 2013 attack.
Stephen Silva, 21, appeared in Boston federal court to enter his plea on charges that include drug violations as well as having possessed a Ruger P95 9mm pistol with its serial number filed off.
Prosecutors say Silva possessed the firearm in February 2013, two months before the bombing suspects, Dzhokhar and Tamerlan Tsarnaev, used a similar weapon to kill a Massachusetts Institute of Technology (MIT) police officer three days after the bombing at the Boston Marathon that killed three people and injured more than 260.
Investigators recovered a Ruger P95 9mm pistol from the scene of a shootout between the alleged bombers and the police the next morning.
Silva's attorney last month cited prosecutors as telling him they believed the weapon his client is accused of having possessed was used in the shooting.
Federal prosecutors have not said if the case against Silva is related to the investigation into the bombing and neither the Tsarnaev brothers nor the MIT offer, Sean Collier, were mentioned in the indictment.
Jonathan Shapiro, Silva's lawyer, outside court on Wednesday emphasized that the indictment does not draw a connection between Silva and the alleged Boston Marathon bombers.
"He has not been charged with any connection to the Boston Marathon bombing," said Shapiro. "This kind of publicity is going to affect any trial."
Four other people who crossed paths with the Tsarnaevs have been charged with interfering with the investigation or failing to fully cooperate with police. One, Kazakh exchange student Azamat Tazhayakov, was found guilty last month of obstruction of justice and conspiracy.
Tsarnaev is awaiting trial on charges that carry the death penalty. His brother, Tamerlan, was killed in the shootout with police. (Editing by Scott Malone and Bernadette Baum)