Agree with Mr K.
1 - You own the property. It's your tenant. You are responsible for the security deposit. Period.
2 - You have recourse against Larry. You can sue him for indemnification. You can report the theft to the police.
3 - You might have recourse against the new company but if you want to invoke Johnson v Amsted you'll need a copy of the purchase agreement between the two companies and you can bet that they aren't going to give it to you unless you sue and get it during discovery. That's probably not a good idea if you want their cooperation helping you go after Larry.

