San Francisco police are warning dog owners in the city’s Twin Peaks and Diamond Heights neighborhoods about a number of poisoned meatballs that have been found along streets in that area.

On Wednesday, at about 8:30 a.m., a dog ingested one of the cooked meatballs while being walked by its owner, police said. The dog became very sick and was taken to a veterinarian for treatment.

The dog’s owner and neighbors collected other meatballs from the streets, and police said it appears they contain a poisonous substance. Tests are under way to determine the nature of the substance.

Police said dog owners in the area of Crestline Drive and Burnett Avenue should be especially cautious.

Anyone with information on the case is asked to call the Police Department’s anonymous tip line at (415) 575-4444 or text a tip to TIP411 with “SFPD” in the beginning of the message.

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