DALY CITY, Calif. (KGO) -- A frightening story in Daly City after neighbors heard a man yelling for his life as he was being mauled by a dog. Police ended up shooting and killing the animal. The attack happened Monday morning on Schwerin Street.When Daly City Police arrived at 976 Schwerin Street, the time had long passed when they could prevent an attack. All they could do---shoot to kill."He was playful and friendly so something happened to him but I don't know. I am just surprised," said neighbor Lray Torres about the assailant, a neighborhood Rottweiler.Police shot and killed the dog as he attacked 30-year-old Gil Galang in his own backyard, Monday morning. His father, Avelino says the dog fought his way through the fence to do it.Next door, Patricia Ochoa heard the screams, then watched the attack as the victim begged for help."We threw a knife so he could use it but it looked like the dog had already broken one of his arms. It was in his mouth. Very graphic."Another neighbor tried to spray water on the dog but without success. Daly City Police arrived as soon as possible. "After that, police shot the dog," said OchoaAn ambulance took Gil Galang to San Francisco General Hospital. Monday afternoon, his parents described him as being in critical condition while waiting for a long-term prognosis."I just wish we could have done more," said Ochoa."I am worried about my son," said his mother, Epifamia Galang.The owners of the Rottweiler did not answer their front door when we stopped by.There is still no word on what caused the dog to attack.