A man suspected of killing three people in New Mexico opened fire on two guards at Universal Studios, killing one and wounding another, before being wounded and captured by sheriff's deputies, police said Friday.

Investigators said they had no idea why the man, identified as former mental patient Nathan Trupp, 43, opened fire about 5:40 p.m. Thursday on the security guard station outside the main employee gate to the movie and television industry amusement park. Guard Jeren Beeks, 27, of La Crescenta, who had recently switched to the night shift, was killed.Trupp was critically wounded during a running gun battle with a sheriff's deputy who arrived as Trupp was running away, Deputy Hal Grant said. The deputy was not hit.