He wasn't a cop that I see, and he did call 911. He called 911 then started driving around his block when he saw his daughter in the passenger side with a man who had been charged with raping her. He ran for office because of what he felt was corrupt handling of his case.

Some details I found with a quick search

No one can really say how much of an execution vs crime of passion this was because the video of the incident was lost by the sheriff's office. The judge probably dismissed the charge of second degree murder because the normal thing with spoiliation of evidence is to assume it is favorable to the other party. If he really did execute the guy the cops should have properly presented the evidence.