Animal Care and Control officers are asking for the public's help in finding the person who hid the meatballs in areas where dogs and cats could find them.
Acting Lt. Denise BonGiovanni says she found 34 meatballs hidden in carports, behind stairwells, along curbs and in bushes on Saturday. She says a resident handed her another ball of raw meat she took from her dog.
The San Francisco Chronicle reports that police will test them to determine if they are poisonous.
Last July, a 7-year-old dachshund named Oskar died after eating a meatball laced with strychnine. Another dog was sickened. Police never found the suspect.