I had owned the vehicle for 13 months at the time and never had the problem before. This was the only occasion that it occurred and has not been duplicated. The alarm didn't go off when the fireman opened the vehicle.
My question was: "Has anyone else had a problem with their Toyota locking on its own?" Do you know the answer to that question? If that has been a problem for other people, then I'd like to know what causes the problem.