It's a refrain that we hear again and again in San Francisco: Don't leave anything of value in your car, or it will be stolen. So, yes, it's irritating when everyday civilians ignore that advice and get smashed-and-grabbed. But it's more than irritating — infuriating? confounding? — when law enforcement officers, who must know better, leave their deadly weapons in their parked cars, which are then robbed. But that's what happened yet again this weekend, and this time the offending cop was an FBI agent.

According to San Francisco Police Department spokesperson Officer Carlos Manfredi, between 12:30-12:40 Sunday afternoon, a vehicle belonging to an FBI agent was broken into at Hayes and Pierce Streets, on the southern edge of Alamo Square Park.

Manfredi says that when the agent's vehicle was robbed, his "40 Cal. Glock 27," and his "I.D. Badge and Credentials" were taken.

"He returned back to the vehicle and within 15 minutes, he found his rear window broken out and his FBI department-issued, fully loaded glock 27 and ankle holster gone," ABC 7 reports police dispatch as saying at the time of the robbery.

Speaking with the Ex, FBI spokesperson Prentice Danner said “We are aware that that’s been reported,” and that agents are expected to secure weapons in their vehicles.

“As a rule, we don’t talk about stolen firearms from agents," Danner said, but if the agent was negligent the issue is “handled accordingly.”

According to the LA Times, the agent isn't from the Bay Area, and "was visiting San Francisco with his family."

The Glock was his personal handgun, not his service weapon, they report.

Of course, this is just the latest in a series of cops who lost track of their firearms in the Bay Area. Here's a quick rundown of the most recent:

The issue of guns stolen from vehicles was serious enough that earlier this year, SF passed a law requiring gun owners to secure their guns "with lockboxes affixed to the vehicle or in fully enclosed locked trunks with automatic release levers disabled." Violators could face misdemeanor charges, six months in jail, or a $10,000 fine. While that law does extend to law enforcement agents, it's still unclear if it will apply in Sunday's case: According to the Ex, the law "exempts local law enforcement if they have policies of their own, and "does not apply to on-duty law enforcement from outside jurisdictions."

So what does that mean for a reportedly vacationing Fed? Your guess is as good as mine, as by publication time both the FBI and SFPD had failed to respond to SFist's questions regarding the case.

Update: According to the Chronicle, the gun was recovered today after a FBI SWAT team raided a home close to Keith and Thomas Street. A suspect was taken into custody, and while the gun was recovered, the FBI badge and credentials were not.