An Alabama inmate serving a life sentence for robbery has been indicted in the 1974 fatal shooting of a Texas police officer.

Prosecutors joined police in Alice, Texas, on Tuesday to announce the May 10 indictment of Roberto Lopez on a capital murder count. Officer Matthew Murphy was shot during a traffic stop in Alice, 120 miles (193.11 kilometers) south of San Antonio.

Alabama Department of Corrections records show Lopez in 1981 was sentenced to life in prison without parole for robbery.

Alice police in 2017 identified Lopez as a suspect. An affidavit says the inmate bragged about killing a "narc" named Murphy. The victim previously was an undercover narcotics officer.

Alabama corrections officials didn't immediately return messages Wednesday. No information could immediately be located for an attorney representing Lopez.