NEW ORLEANS (AP) — A New Orleans man has pleaded guilty to multiple crimes, including murdering a federal witness, in connection with a conspiracy involving robbery of drug dealers.

Fifty-four-year-old Gregory Denson faces a possible life sentence. However, a plea agreement filed in federal court Friday states that prosecutors agree that a 30-year sentence would be appropriate in the case.

A news release from Acting U.S. Attorney Duane Evans said Denson was the last among nine people to plead guilty in the conspiracy. It says they committed home invasions of known drug dealers, robbing them of drug trafficking proceeds.

Prosecutors said Denson murdered a witness, Ellery Boyd, to keep him from reporting the crimes.

Sentencing is set for March 8.