I still find it hard to believe someone went through the trouble of bringing a hose to a lake, unscrewing your lids, and spent the time to suck water through the hose strongly enough to create sustained flow, then held it in place (or secured it another way) and let it fill and sink your boat. - seems like more work and risk to the "vandal"... when someone could kick a hole, shoot or blow up your boat much easier.
I live in florida so i know how INSANE people can be around here.. so it is possible, but i still think it make more sense that you had a failure somewhere /somehow.
I would recommend you put the boat on a trailer or lift it somehow and fill it with a few 100 lbs of water and see if it leaks out somewhere... and do a compressed air bubble test
glad your afloat!
MN3