If you think your He really did assult your dog I'd call the police.
I'd never advocate violence, but if someone hit my lab they'd get the living snot kicked out of them
I second the vet trip regardless, although if you bring the dog in and say your roommate beat him, the vet will most likely want to report it to the police.
Why on earth would he do this
Is he wacked on drugs?
-spence