At that point, technically, he should of stopped. He is legally vulnerable for each blow he threw afterward.
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I’ve yet to see any evidence that he pulled him off the kid *then* started punching him. Its quite likely the perp started fighting back the moment dad got his hands on him, justifying the use of force.
Not that I would convict him even if he’d taken a few shots after he’d pulled the pervert off the kid. This is one case in which the much maligned “temporary insanity” defense would be absolutely justified.
I can’t think of msny things capable of causing someone to temporarily lose their reason as witnessing your own child in the process of being molested by some sh*tbag with his pants around his ankles.
Just the thought of it is enough to raise anyones blood pressure a few points.