NOVATO (CBS SF) — Police are investigating a smash-and-grab robbery at a North Bay Costco store Sunday morning, according to authorities.

The thieves struck just after 10 a.m. Sunday morning at the Costco in Marin County just off Highway 101. A manager at the store confirmed the robbers targeted a  large display case in the jewelry department that was completely  emptied.

Police say three men walked into the store wearing surgical masks and used a hammer to smash the glass cases and grab the jewelry.

Witnesses said the three suspects were all young African-American men.

The suspects ran away with at least one bag of jewelry and watches, according to a witness.

The masked bandits race back out of the store and into a waiting car.

Police are now looking for the getaway car, a black Chevy Sonic with paper license plates.

Novato police hope this new surveillance video will help them find the Costco thieves.

Sunday’s robbery is similar to two other jewelry heists in May at a Costco in Danville. Danville police made one arrest, after an employee tackled one of the masked burglars.