I read this in a gun mag's "stupid criminals" section. This occured in 1988. Three guys went into a restaurant and hold up the place. It turns out they picked the wrong place at the wrong time since there were three FBI agents having lunch there. The agents pursued the robbers and got into a shoot out in the parking lot. One criminal was seriously injured and one FBI agent suffered minor injuries.
Funniest part... It was my (now) father-in-law's restaurant.
The ATF should be a convenience store instead of a government agency!