Sounds like you have a true police bike. They were wired up to use the key to start, just like a car. The civilian police bikes used the same switch, except the start position (turning the key all the way right as if you would start a car) was not wired.
Keith,
Mine is totally civilian. No floorboards, no big aluminum dash, no radio mounts or any of that other cool stuff. Perhaps someone wired it that way at some point. Who knows what that bike has been through over the past 29 years. If only it could talk.