One night, a man receives a call from the police. The police tell the man that his wife was robbed, murdered, and her body dumped in a remote location, and that he should reach the crime scene as soon as possible.
The man drops his phone in shock, and drives 20 minutes to the crime scene. Though the man does not have any evidence of committing the murder on his personal being (no blood or other signs of foul play on the car or any possessions) as soon as he reaches the crime scene, and before he can say or do anything, the police arrest him on suspicion of committing the murder (he will, of course be judged by a jury of his peers, etc.).
Without any sign of typical evidence, why do the police think that he committed the crime?
It should be noted that this takes place in the typical world, without aliens, super powers, or unlimited quantities of any material.