Deputy Bill Koehler, is one of the few Jericho law enforcement officials left after escaped prisoners kill the other deputies. He works with Jimmy Taylor to enforce the law.
Bill is involved several of Jericho's storylines. Bill investigated the theft of pesticides from Gracie Leah's Market, going so far as to almost accuse Stanley Richmond of the theft, but found no evidence of the pesticides. When Stanley harrasses him about it, he replies "Look, I'm just doing my job."
Bill is also involved in the kidnapping of Mayor Grey Anderson, when Grey was held hostage at gunpoint by Roger. Bill (assuming he's the best shot of the deputies) is seen climbing a ladder to a roof, with a sniper rifle. Jake tries to talk him out of it, but Bill replies "If I get the shot, I'm going to take it."
Bill is seen in various episodes, even gaining more screen time in the second season.
- In episode seven of season two, while impersonating a soldier, the name-tag on his uniform reads the name "Muck." This is likely a reference to one of Richard Speight's most well known roles, that of Sgt. Warren Muck in the series Band of Brothers.