A year ago, he was a homeless down and out. Today, he is one of the city's frontline crime fighters. The remarkable transformation of Rocky the Rottweiler from street dog to police dog came after an animal welfare charity introduced him to the Hong Kong Police dog unit. He graduated from police dog school last month after 16 weeks of intensive training. The two-year-old was found last September by inspectors from the Society for the Prevention of Cruelty for Animals (SPCA) wandering around Yuen Long with an injured paw. This opportunity provides [Rocky] with the chance to use his inborn traits and skills SPCA director Sandy Macalister He spent three months in SPCA kennels where - in a sign he was destined to fight the forces of evil - he was randomly assigned a case number ending 007, the same as Ian Fleming's spy James Bond. Rocky even acted as a blood donor to help save the lives of two dogs. However, his large size and breed - Rottweilers have a reputation for being aggressive - meant no one was willing to take him home with them, said SPCA welfare operations manager Dr Judy Wan Hon-chi. In December, his luck changed when officers from the police dog unit visited the SPCA and mentioned in passing that they would like to adopt and train a rescue dog. "One of my colleagues immediately thought of Rocky," said Wan. "He was relatively obedient and very playful, but he was not happy in kennels. He was a dog who was happiest when he was out doing things with someone." The officers were impressed and recruited Rocky on the spot. One week later he was adopted officially by the police and living at the Police Dog Unit headquarters in Sha Ling, in the New Territories. He received obedience training, was taught how to attack criminals and learned to get used to travel by car and boat. A group of SPCA staff and volunteers presented Rocky with a card featuring him wearing a police hat. "One volunteer who was very close to Rocky was almost in tears," Wan said. "She said: 'Look at my baby, he is all grown up now, and he has a job.'" A police spokesman said: "Rocky's aggressive appearance is actually good deterrence to would-be criminals. … Rocky is now well tamed, but he will assist his police dog handler readily if there are troublemakers." SPCA executive director Sandy Macalister said: "With the SPCA adoptions, our focus is on the dog and finding the best match for both dog and human. Rocky was most likely a pet once, and that didn't end well as he was most likely abandoned. "He is basically bred to be a working dog and now this opportunity provides him with the chance to use his inborn traits and skills." Rocky joins more than 110 other police dogs that assist officers on patrol and sniff out explosives and drugs.