That really stinks. One thing I've learned is that once a predator finds a way to your flock, it will keep coming back until all the chickens are gone. Hopefully a blast of hot wire to its face will cause it to reevaluate how "easy" these chickens are.
Is the ban truly on any type of electric deterrent? Or just a full-on electrified fence. If you would run a single wire around your coop and run, that might do it, especially if hang hang some bacon or ham, to ensure the bear actually bites at the wire the first time it encounters it.