I know people have contacted national media organisations. Beyond that there isn't a lot we can do.
We may not be able to deport him or re-try him - but we can make sure that all horse owners are aware of this incident so it does not happen again. An online petition does exactly that - raise awareness.
What else is there that the individual can do? Beat down his door? I imagine that this case has already taken his employment, possibly some of his friends, and community respect. All that is left to do is warn people so the this doesn't happen again. It's pretty horrific, and just makes me trust the horse indust
Thank you for posting this link though :)