We do not know, it is possible he had an accomplice but quite honestly the fBI have amazing video enhancement capabilities and it is likely they would have spotted a second person in the car, likely does not infer certainty. A whack of a hammer on the head will down most people pretty quickly but we talked it all out before ad infinitum. We do not know . He could have shot her too, why clean the passenger door? Is his wife testifying against fBI?