See Spot Run

See Spot Run is a 2001 CanadianAmerican comedy film about a mailman who takes in a stray bullmastiff, the titular Spot, only to learn that it is a trained FBI dog that has escaped from a witness protection program and is targeted for killing by a crime boss. The film was shot in Vancouver, British Columbia, Canada.

After Agentescapes, he meets Gordon Smith David Arquette, who works as a mailman. The mailman dislikes dogs and has volunteered to take care of James, the young son of his neighbor Stephanie Leslie Bibb. Gino and Arliss have continued their search for the dog. Agent 11, whom James names Spot doesnt want to catch balls or frisbees because Murdoch told him not to play when he was a puppy, but he eventually starts to play with the boy James and Gordon like a normal dog. Later, Gino and Arliss try to kill the dog while he is with Gordon and James at a pet store, but he outsmarts them.When the FBI finds out that Spot is living with Gordon, they take him back. The dog escapes and finds Gordon and James again. Talia returns and attempts to kill the dog, but is outsmarted, captured and imprisoned. ........

Source: Wikipedia