UPDATE: Nevada police have identified the IHOP shooter as Eduardo Sencion, a 32-year-old with no prior criminal record.

Sencion opened fire at an IHOP restaurant in Carson City, Nev., on Tuesday morning, killing four people -- including three National Guardsmen -- before turning his AK-47 assault rifle on himself. The Reno Gazette Journal reports that, according to witnesses at the scene, Sencion first shot a woman standing next to a motorcycle in the parking lot before entering the restaurant and opening fire.

The Associated Press reports that, according to authorities, after the shooting began, Sencion "marched resolutely toward a table of uniformed National Guard members before shooting each one of them, and fatally wounding three of them." Witnesses say he reloaded at least once.

According to the Gazette, Sencion was born in Mexico but had become a U.S. citizen. There was a "Support Our Troops" yellow ribbon decal on the blue minivan that he drove to the restaurant, although he does not appear to have had any direct connection with the military. He also had no known affiliation with anyone in the restaurant, police say.

Sencion's family says that he had mental problems but declined to elaborate, the AP reports.