I get the feeling he didn't try to cover his ass, and when the cops asked if he did it he would say, Hell yeah, I did it. I have no evidence of that, so I may be wrong.
But did he do the right thing? His other two choices I see, are walking away, or making a big, continuous, public stink about the dude until the DA took action or everyone for 100 miles was keeping an eye on the dude.