The SF Public Utilities Commission says that more than 400 utility covers have been stolen off San Francisco sidewalks over the last two years, and the police department is urging residents to tattle on anyone they see doing this.

As the SF Public Utilities Commission tells it, more than 400 utility covers have been stolen off of San Francisco sidewalks over the last two years. That’s odd, because these would seem to have little value or use to anyone who is not a public utilities worker. But the gaps left on the sidewalks by these covers’ removal presents a real tripping hazard for pedestrians, and now NBC Bay Area reports that the SF Police Department is trying to figure out who’s responsible for this and bring these thefts to a halt.

The utility covers in questions are seen above. Some of them are dark oval-shaped covers with the name and insignia of the San Francisco Water Department, others are light-colored concrete rectangles that bear the letters “SFPUC.”

“The San Francisco Police Department is urging members of the community to be on alert for the theft of utility covers that leave sizable holes in city sidewalks that create a tripping hazard for pedestrians,” the department said in a press release. “The SFPD is investigating the thefts of these utility covers and is assisting in the recovery efforts.”

The department adds that if you see someone in the act of stealing one of these things, or know anyone hoarding them, you should call 911, as removing them or stealing them is a crime.

Whereas if you see missing covers on the sidewalk, you should call 311 to report this, so the SFPUC can get around to replacing them as quickly as possible.

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Images via SFPD