Wilson whereabouts is learnt on Chapter 9 where Tom tells Nick that Wilson came to East Egg and while there Tom tells Wilson that was Gatsby's car that killed Myrtle. Police suspect that Wilson has spent time tracking down the owner of the car that ran down his wife and we have in mind that Wilson believes that his wife was not killed accidentally. He suspects that the owner of the car intended to kill Myrtle. Wilson tracks down Gatsby planning revenge believing that he is doing Gods will.