try the King Solomon's technique.... "

"to determine who's the one is the real mother...
wont certainly allow to put her child in peril..."

considering you are already a valuable/longtime boarder to your landlady/landlord... bring up your problem to your landlady/landlord.... just attempt to ask both of your roommate to pay for the items lost...

perhaps true colors will then popped up whose guilty...

if you wont get back your losses... at least you will be justified to learn from it...