Red (2008)

Elderly, reclusive widower Avery Ludlow is left distraught when his only companion in life - a 14-year-old dog named Red - is murdered by three teenagers. After tracking the youths down, Avery demands the parents take action against the youths but after being turned away, he decides to dish out justice by any means necessary. Thriller, starring Brian Cox, Noel Fisher, Tom Sizemore and Kyle Gallner.