SANTA FE, N.M. — Authorities in New Mexico have arrested a man after police say he fatally shot two people and streamed part of the assault on Facebook.

Alejandro Alirez, 23, of Las Vegas was arrested Sunday on multiple charges including first-degree murder, aggravated assault on a peace officer with a deadly weapon and shooting at an occupied building, the New Mexico State Police said in a statement Monday.

Police said his girlfriend, Cristal Cervantes, 33, and her grandfather, Victor Cervantes, 89, who both lived at the Las Vegas home where the shooting occurred, died at the scene.

San Miguel County Sheriff's deputies originally responded after being called by Alirez's mother who said her son was acting "irate" and had a handgun at the Cervantes' home, an affidavit said.

Arriving officers said the suspect fired shots at deputies, who then called the New Mexico State Police and the Las Vegas Police Department for backup. No deputies were injured.

Alirez surrendered after crisis negotiators spoke with him by phone, authorities said. Police then discovered two bodies in the home.

New Mexico State Police said part of the shooting was livestreamed on Facebook.

"Agents observed that Alirez livestreamed a portion of the event, including Alirez walking around inside the residence with a handgun and shooting Cristal Cervantes," the agency said in a statement. He could then be heard saying he "shot her grandpa," as well as, "I killed this guy. My girlfriend is still alive."

Alirez allegedly waived his Miranda rights at the state police department station and told officers that a few weeks prior to the fatal shooting, he began to notice he was being molested in his sleep, the Santa Fe New Mexican reported.

Alirez believed his girlfriend was allowing people to come into the residence to assault him, and that there were "other children being molested" and he needed to "save" them, the criminal complaint said.

Alirez allegedly told officers he had purchased a .45 Hi-Point pistol last week that he intended to use to kill his nieces and nephews.

Online court records didn't list an attorney for Alirez who could comment on his behalf.

Alirez is scheduled for a hearing Friday to determine the possible conditions of his release, followed by a preliminary examination Nov. 24.