The gun was taken from a car parked inside the locked parking lot on Blum Road in Martinez. As many as three cars were broken into. Officers believe someone cut a hole in the fence to get in.
A Colt semi-automatic rifle is missing, along with 120 rounds of ammo.
It happened sometime between 1:30 a.m. Monday and 1:30 a.m. Tuesday. It all happened while officers were working just feet away, inside the building.
"It is staffed 24 hours, 7 days a week. The kind of brashness it takes to do something like that, I can't even imagine. I can't even imagine trying to do something like that," said Ofc. Tom McGuire.
Anyone with information on the theft should call any local highway patrol office.