An off-duty Secret Service officer killed a dog in Windsor Terrace, Brooklyn just before 10 p.m. Monday evening, NYPD sources confirmed. The agency employee was rounding a corner on the block of the Kensington Horse Stables, just outside of Prospect Park, when, he said, the dog charged, and he fired one shot that killed the animal, according to police, who said the individual remained on the scene after the shooting.

Walker Blankinship, the manager of the Stables, said he was sitting in his truck when he heard a single gunshot, immediately followed by two men and a woman arguing, with one man loudly doing most of the talking: "I can't believe you let the gun go off!"

In a statement, the Secret Service told The Daily Beast: “An off duty Secret Service employee was involved in the shooting of an unleashed dog in Brooklyn, NY this evening. As this is an ongoing NYPD investigation, the Secret Service will not have further comment.”

The body of the dog, which appeared to be about 35 pounds, remained on the scene, under a sheet, as of midnight. Also under the sheet was a leash.

When police cleared the scene shortly thereafter, the man who'd been with the woman as police arrived picked up the dog and placed it in the back of his SUV before driving away.

—Anna Kaplan contributed reporting