Lt. Kristen Roman of the Professional Standards and Internal Affairs office said the officer, whose name and gender were not disclosed, discharged the electricity weapon while performing a checkout procedure, the Madison Capital Times reported Tuesday.

However, the officer did not ensure that the Taser was not loaded with an air cartridge, and it fired a bolt into the officer's hand, delivering a massive electric jolt and injuring the hand.

A summary of the event released by the Madison Police Department said the officer's offense violated Madison Police Department policy and demonstrated a disregard for safety.