Seriously, this is messed up. People jumping to conclusions isn't great either. If it's two shops, its probably real and who knows, could be your tank or your dream someday. Running a small business is tough and things like this are no way to lose out on all that hard work. I hope they find out who it is.
Could you imagine if it got to the point where all the tanks and sumps were closed up and you had to be escorted through stores? Ugh, no thanks.