A 12-year-old boy was arrested Friday for killing his dog. Salinas police officers responded to the 3-hundred block of front street, after receiving a 9-1-1 call from someone who then hung up. The resident would not open the door, but once officers gained entry, they discovered the dead dog. Salinas police say they boy admitted to killing the animal because he was mad at it. He was booked into Monterey county juvenile hall for felony cruelty to an animal.