Police arrested Matthew Weatherspoon in the Monday puppy attack, said Denver police spokesman Detective John White. He was being held on investigation of felony aggravated animal cruelty.

Someone found the American bulldog, named Diamond, wandering around an apartment complex at 6875 E. Iliff Ave. early Monday morning.

The owner of the American bulldog pup said he became angry after the puppy bit him, so he grabbed a knife and repeatedly stabbed the dog, "slashing his face," Doug Kelley, director of Denver Animal Care and Control, told the Denver Post.

The puppy's owner, who had no visible bite marks, said he threw the puppy outside because he was mad the dog was bleeding in his apartment, Kelley told the newspaper.

The puppy was rushed to VCA Alameda East Veterinary Hospital, where she underwent surgery for knife wounds to her face, neck and abdomen, hospital spokeswoman Lauren Immel told 7NEWS.

"Diamond has, of course, captured the hearts of the entire staff at Alameda East," she said. "She is an absolute doll, very sweet."