SAN MARINO (CBSLA.com) — A boy brought a stun gun designed to look like a smartphone to a school in San Marino, prompting a police investigation.

A parent reported last Saturday that a 12-year-old boy had shocked another child with a stun gun by the lunch tables near the basketball courts at Huntington Middle School, San Marino police said Thursday.

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The police investigation determined the stun gun was used in a joking manner, with no threatening intent, but possession of a stun gun by a minor is illegal, so the investigation soon shifted to determining where the child got the device.

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Officers say the boy bought the stun gun at the “As Seen On TV Products” store at the Westfield Santa Anita Shopping Center in Arcadia. The store owner confirmed she sold the device to the boy, but said she didn’t realize it was illegal to sell a stun gun to a minor.

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San Marino police officials say the investigation is ongoing, and appropriate charges, if any, will be determined after the case is reviewed by the Los Angeles County District Attorney’s Office.