Casino cam shows masked gunman knocking off East Bay card room

An armed assailant robbed the California Grand Casino in Pacheco early Monday morning. An armed assailant robbed the California Grand Casino in Pacheco early Monday morning. Photo: Contra Costa County Sheriff Photo: Contra Costa County Sheriff Image 1 of / 4 Caption Close Casino cam shows masked gunman knocking off East Bay card room 1 / 4 Back to Gallery

An assailant wearing a chilling Halloween mask and carrying a semiautomatic rifle pulled off a brazen robbery Monday morning at a card table at the California Grand Casino in Pacheco, officials said.

The man knocked off the casino on the 5900 block of Pacheco Boulevard around 4:45 a.m. before fleeing with an undetermined amount of loot, Contra Costa County sheriff’s officials said.

They released surveillance photos of the masked gunman sticking up a pai gow poker table along with pictures of the getaway vehicle.

The robber, described as a 6-foot-tall man weighing 200 pounds, drove away in a vehicle described as a Mercedes Benz or BMW. No one was injured in the holdup.

The gunman was wearing a full-face mask, a black hoodie, dark pants and orange gloves.

Anyone with information was asked to call the sheriff’s office at (925) 313-2662.

Evan Sernoffsky is a San Francisco Chronicle staff writer. Email: esernoffsky@sfchronicle.com Twitter: @EvanSernoffsky