His owner was charged with torturing and injuring him, and Alvin was nursed back to physical health, society officials said. Emotional scars remained, however, including an aversion to people he did not recognize, as well as unfamiliar clothing or objects.

But over the course of many sessions, Ms. Wells has taught Alvin to trust people he does not know. His progress has been heartening to Ms. Wells, who uses a variety of outfits, including things like a bright yellow raincoat and a straw hat. Dogs like Alvin “come in broken and hopeless and they leave happy and healthy,” she said.

Society officials said they began the police partnership with the hope of it would carry wider enforcement. A.S.P.C.A. workers have conducted training at the Police Academy on subjects such as animal cruelty laws, forensic investigation, pet hoarding and blood sports, like dogfighting.

The transfer of enforcement responsibilities has led to a surge in the number of animals being rescued and in the number of people arrested on charges of mistreatment, society officials said.

From 2013 to 2014, the number of abused animals, most of them dogs, handled by the society increased to 422 from 133, with arrests in cruelty cases rising to 134 from 42, according to the organization. The increase has been even sharper this year, with more than 560 animals taken in by the end of September, and more than 125 arrests.