Albuquerque's police chief says it's "completely unacceptable" that an officer used foul language and called a man he later fatally shot a "lunatic."

Chief Gorden Eden told The Associated Press on Tuesday that Officer Keith Sandy violated department policy when he used an expletive to describe a 38-year-old man struggling with mental illness.

Authorities say Sandy was one of two officers who shot James Boyd following an hours-long standoff in the Sandia foothills in March. That shooting later sparked a violent protest in Albuquerque and an FBI investigation.

In a recording released Monday, Sandy is heard telling a New Mexico State Police sergeant that Boyd was a lunatic who he planned to shoot.

The sergeant later said Sandy was referring to using a stun gun.