It means that he was appointed the temporary sheriff of Multnomah County, Oregon after the previous sheriff retired before his term ended. So John Bunnell was appointed the "temporary" sheriff to finish out his term. He served in that capacity from November 30, 1994 up till May of 1995.

As for the guy in the Toyota, I have no idea if he was a drug dealer. Once a chase is over, the local media usually doesn't report anything more on the story. All that really matters is the chase itself, unless someone else gets injured or killed.

And a little trivia: John Bunnell appeared as a police officer in "Bad Santa." It was quite funny, actually.