Alfonso Hoffman raised his right hand and swore an oath Wednesday -- to uphold the laws of the state and county and perform the duties of a K-9 deputy sheriff of the Transit Policing Division.
After being fitted with a green tactical vest and handed a leash, Alfonso climbed into an armored truck for his first patrol.
The 12-year-old kid crime-fighter, diagnosed with leukemia this year, got a chance to live his dream on Wednesday, joining a Los Angeles County Sheriff's Department K-9 patrol.
He was inspired by his uncle.
"Throughout my years, I really looked up to him," Alfonso said, tearing up, at a news conference. "I'm really happy to be working with the dogs, and training."
He was assigned to train with police deputy dogs Beshai, Tweedy, Hhatton and Xxara. The dogs work for the transit bureau which polices rail and bus lines across the county.
Michael Garcia, Alfonso's uncle, asked his deputy co-workers to help arrange the special day for his nephew.
Garcia said Alfonso's chemo sessions keep him in the hospital for days at a time.
"So to see him smile for a day, it's heartwarming," Garcia said. "The visits usually get him very sick and tired, so what happened today will lift up his spirit. He's a fighter."