A convicted murderer is dead after he was killed by a fellow inmate at the Oregon State Penitentiary .
According to the Department of Corrections, 45 year old Joseph Akins was found dead inside his cell around 10 am Saturday.
The prison was put on lockdown, while investigators examined the scene.
The state medical examiner's office ruled that Akins died from "inflicted trauma".
Meantime, police are holding an inmate as a possible suspect, however no charges have yet been filed.
Akins was convicted of murdering a Milwaukie woman in 1994, although he was not convicted until 2008.