Cecile and Victor Stanton of Jericho, N.Y., alleged in the suit that Beverley Jeffries of Pasadena refused give their beloved dog back for unspecified reasons.
The Stantons and Jeffries signed a contract in February in which Jeffries was given temporary custody of the dog while the Stantons retained ownership. Jeffries allegedly refused to return the dog to the Stantons in May.
The suit alleges Jeffries had the dog, known as Justin to its friends, neutered without their permission sometime in April.
The alleged procedure was more than a rude gesture, ABC News noted, since AKC Grand Champions like Justin can fetch a hefty stud fee. The Jeffries contended the incident cost them $100,000 in breeding value.
ABC said Jeffries could not be reached for comment.