A Massachusetts man who at one time was in possession of the gun that the Boston Marathon bombers used to kill a police officer has pleaded guilty to related charges.

Merhawi "Howie" Berhe (muhr-HAW'-ee burr-HEE'), of Cambridge, pleaded guilty Thursday in federal court to possession of a firearm with an obliterated serial number. Sentencing is scheduled for June.

Prosecutors say Berhe gave the gun to Stephen Silva, who later gave it to convicted marathon bomber Dzhokhar Tsarnaev (joh-HAHR' tsahr-NEYE'-ehv). Prosecutors did not allege Berhe had advance knowledge of the marathon attack.

Tsarnaev and his older brother, Tamerlan (TAM'-ehr-luhn), used the gun several days after the April 2013 bombing to kill Massachusetts Institute of Technology officer Sean Collier in an attempt to steal his weapon.

Silva previously pleaded guilty to related charges.