Yerington, CA – Steve Rubenstein, Chronicle Staff Writer

Three East Bay residents were among four people killed in a rural Nevada motel room, and investigators are trying to determine Monday whether they had been overcome by carbon monoxide fumes from a heater.

A maintenance man discovered the victims Sunday at the Casino West Motel in Yerington, about 50 miles southeast of Reno, said Scott Huntley of the Mason Valley Fire Protection District.

“Carbon monoxide is being strongly investigated,” Huntley said. “We’ve gotten some elevated readings from inside the room.”

Huntley said the bodies showed no signs of violence or foul play.

The victims were identified as Juan Pablo Chavez, 27, and his wife, Veronica Espinoza Chavez, 20, both of Richmond, and Donna Vega-Robles, 30, of San Pablo. Also killed was Phillip Doll, 26, of Yerington. All four had checked into the motel early Sunday.

One victim was found in a bathtub, with the tap running and water leaking out from under the closed bathroom door.

Huntley said investigators were testing the room heater and also a heater for the motel swimming pool, which was adjacent to the room. Autopsies were being conducted Monday.