Roberto Martinez, 25, who abused his girlfriend’s puppy so badly that it lost its leg pleaded guilty Friday and was sentenced to a year in jail, according to the Bronx District Attorney’s Office. 

He was caught on video last September lifting the approximately eight-month-old pooch “Sassy” by the harness and slamming her to the floor from shoulder height, according to prosecutors.

“The defendant’s abuse of an 8-month old dog culminated in a leg injury leading to amputation of the limb,” Bronx District Attorney said. “Such inhumane actions warrant a jail sentence. We will not tolerate cruelty to defenseless animals.”

During the incident, Sassy landed on her backside and tried to run away from Martinez, but couldn’t get away because she could not move her right hind leg.

That did not stop Martinez from grabbing the terrified dog by the neck and pushing her up the stairs, the DA said.

His girlfriend brought the dog to the ASPCA and told a story about how Sassy had fallen down the stairs. But workers there discovered broken ribs and other evidence of prior abuse, and contacted the police, according to prosecutors.

Nearly a week after the attack, the dog’s right hind leg had to be amputated.

Sassy has now been renamed Sally and also has a new home, according to Howard Lawrence, vice president of ASPCA’s Humane Law Enforcement division.

He said he was grateful that the animal was rescued from “a life of cruelty and pain” and that her abuser had been brought to justice.

Martinez, who was remanded pending sentencing for aggravated cruelty to animals, has to register as an animal abuser with the state and cannot own an animal for five years.