Strange ending...
The car WAS found but his body was not. The last scene shows a discussion by two of the lead (forgot their names) saying that the locals said the "current" could have washed him away.
They seemed to think that the missing man had planned all this and the guy who claimed to run him off the road was in on it with him. They mentioned they would not be surprised if Missing Man's second wife and child are suddenly missing themselves...
Very interesting, I thought. I hope there's a continuation.