SAN DIEGO (WPVI) -- A Southern California sheriff's deputy is under fire after being caught on cell phone video using his taser on a 13-year-old boy.Police are now coming to the deputy's defense -saying the teen was resisting arrest.The incident is once again sparking questions about police brutality.Police say the boy was a runaway and had done to five times before.They say the teen refused to listen to the deuputy trying to bring him home and while being restrained, the teen bit him hard - leaving visible marks.That's when the deputy reportedly used his Taser twice - using roughly 50 volts of electricity."I think he bit the police officer because he couldn't breathe," said one witness.Police say the deputy was just doing his job, regardless how it might look in a brief video."Use of force is never something pleasant to watch, believe me. But when it's looped and shown over and over and over in teh same clip and portrayed as the actual incident, I think that misrepresents what really happened," said Sheriff Bill Gore.Police say the deputy did not put the teen in a choke hole, as witnesses claimed, and the teen could have avoided the whole ordeal if he'd just obeyed the deputy's commands."When you approach somebody, whether they be a juvenile or adult, and you can legally take them into custody, and they become that unruly, you have to go to some means to take them into custody," said former FBI agent Brad Garrett.Because he was Tased, the teen was checked at a local hospital and is reportedly doing fine.He was booked Tuesday morning into a juvenile hall on charges of resisting arrest.