A dog owner in Colorado claims that when he used a dog-sitting service to care for his dog while he was away, he came home to find shirtless men, a bottle of lubricant and a camera in his living room.

Jimbo may have seen unspeakable things performed by the person hired as his dog sitter. Klete Keller of Colorado Springs, Colo., booked a sitter on a popular dog-walking app, Wag! Though the service ...