The officer said he shot the dog because he felt threatened.
Dallas police say around 1:30 p.m., the off-duty officer was walking his dog when another dog, a 6-year-old retriever mix named Princess, attacked near Capitol Avenue and Bennett Avenue.
Police say the officer fired his weapon, shooting Princess.
Juan Torres says Princess was his aunt's dog, along with a 5-year-old pit bull named Rocky.
He says they both dug a hole on the side of the garage and went out front, and that's when the officer's dog was attacked.
Witnesses say the officer followed the dogs onto their owner's property.
Torres says the officer shot three times, but only one bullet hit Princess and grazed Rocky.
Torres says he then confronted the officer.
"I asked him why he shot; then he asked me if I would have done the same thing," said Torres. "I said no. He got mad and started coming at me, and that's when his fellow officers backed him up and took him into the car."
The off-duty officer sat in the patrol car, and after about two hours, FOX 4 saw him get his dog back and walk home.
Torres says both Rocky and Princess have never acted like this before and understands why the officer protected his dog, but says shooting at them was overboard.
The Torreses were given two citations -- one for not having updated vaccination record and one for the dogs running loose.
As for the officer, Dallas police won't comment on possible charges, but attorney Pete Schulte says it's a possibility.
"Technically under the law, the officer could be charged with animal cruelty, but I think there's a defense," said Schulte. "At least one or two defenses built into other parts of the law that would allow him to avoid criminal penalty associated with it, but animal cruelty statutes doesn't give a defense when it's not on your property."
Even though the officer was off-duty, the incident is still considered an officer-involved shooting, which means the case could go to a grand jury to decide if the officer's actions were reasonable under the circumstances.