Four men were fatally shot in a junkyard Tuesday northwest of Los Angeles in what police called “a case of workplace violence,” authorities said.

The shooting was reported about 4 p.m. at Black Road Auto and all four victims were dead by the time police and medics arrived, Police Chief Danny Macagni told the Santa Maria Times. A suspect was taken into custody, but his name was not released yet.

“This is a case of workplace violence. We have a lot of work to do here. We have a very large crime scene,” Macagni told the local newspaper.

The victims’ names were not immediately released. They were shot at close range, Macagni said. One victim was found outside the junk yard and three were found inside. The gun used in the shooting was found at the scene.

Santa Maria police have not released a motive in the killing. Homicides are rare in Santa Maria, which is in a largely agricultural area on California’s Central Coast. In 2006, there were two homicides in the city of about 85,000 people; in 2005, there were three.

Police aided by California Highway Patrol helicopters searched the area to see whether there were more victims. Macagni said police believed there was "a sole suspect that entered the premises and fired the shots."