Jenkins was in custody at the Barnstable County Correctional Facility awaiting trial for multiple armed robbery indictments when he attacked a corrections officer on June 3, 2012.
The defendant was sentenced to two and 1/2 to seven years in state prison which he will serve after the completion of the nine to ten year sentence he received and is currently serving for armed robbery.
The trial started Wednesday, July 9 and the evidence was completed the next day.
Jurors deliberated for two hours before returning with a guilty verdict.
Massachusetts State Police Detectives assigned to the Cape and Islands District Attorney’s office investigated the case and was assisted by the Barnstable County Sheriff’s Department.
Assistant District Attorney Nicole Manoog prosecuted the case.