TERRE HAUTE, Ind. (AP) — A federal inmate already serving a life sentence has been sentenced to a second life term after pleading guilty to fatally strangling a fellow inmate and stabbing a second inmate at a federal prison in Indiana.

Rodney Curtis Hamrick, 58, was sentenced to life in prison Tuesday by a federal judge in Terre Haute after pleading guilty to first-degree murder. He received a 20-year sentence, to be served concurrently, for his guilty plea to assault with intent to commit murder, the U.S. Attorneys Office said.

Prosecutors said Hamrick strangled inmate Robert Neal, 68, to death and stabbed inmate Richard Warren on Nov. 18, 2018, when all three were housed at the U.S. Penitentiary in Terre Haute.

After Warren informed a prison officer that Hamrick stabbed and assaulted him in Warren’s cell, officers secured Hamrick and confiscated a homemade icepick-like weapon that he used to stab Warren. They then found Neal’s body inside Hamrick’s cell covered in a sheet with a pillowcase tied over his face and neck, with his hands bound behind his back and multiple puncture wounds in his chest.

An autopsy found that Neal had 11 stab wounds to his chest, but that he had died from strangulation, prosecutors said.

Hamrick told FBI agents he planned the attack on Neal and Warren in advance, saying he attacked them “because they were `pseudo-Christians’ — that is, `hypocrites,’” according to his plea agreement, which states that Hamrick also called the two men “snitches.”

After Neal’s slaying and the attack on Warren, Hamrick was transferred to the U.S. Penitentiary in Florence, Colorado.

At the time of the attacks, Hamrick was serving a life sentence imposed in 2007 by the Eastern District of Virginia for using a destructive device in an attempted crime of violence. Prosecutors said Hamrick had seven prior federal convictions for offenses including violent threats against public officials and federal buildings, attempted escape, and multiple offenses involving manufacturing and mailing destructive devices, some of which detonated and injured others.

“It is clear from Rodney Hamrick’s lifelong pattern of violent crime, culminating in the horrific attacks he perpetrated in the Terre Haute prison, that he should never live another day outside of federal prison,” U.S. Attorney Zachary A. Myers for the Southern District of Indiana said in a news release.