I agree with you, Kaldin. And couldn't that very same reasoning apply to why he drove slowly to the scene, arriving some minutes after the police got there? I've never thought that him driving slowly to WHF went against him, for this very reason. Perhaps there was an innocent explanation for that.
Yes, I agree. I can't imagine anyone wanting to get there before the police really. Obviously, if he's innocent, he didn't know if were all dead or if he would find his sister threatening them all with a gun, but even so ...