Then he would have turned himself in. He didn't.
We've all heard the stories where someone was exonerated by DNA evidence. Yes, I'm all for that.
My only question is how does DNA "prove" someone didn't commit a crime? All it can prove is that they didn't find a particular perp's DNA at the scene. Doesn't mean he wasn't there, or had an accomplice, or wore gloves,etc. to prevent leaving a trace.