Guild vault theft

Okay, so i logged onto my paladin the other day, which is a Gm of my guild. i was made aware that someone had stolen things out of the guild vault. i had checked, and the name was shown as "unknown".

A couple things here.

first thing Is there any action to get the guilds items back?
mainly because that individual somehow.. managed to take out almost 20 stacks while the settings only allowed those ranks with withdraw either from 1 to 3 stacks per tab... i suspect a exploit.

secondly, this person who stole the items used a game mechanic to avoid being seen... IE: xfered off the server, or deleted toons right after.


I am curious as to what actions can be taken to get the items back that my guild worked hard for.

the Guild:
The realm:The venture co US
my toon:

Edited so i dont post the names


thank you very much, i hope this can be resolved soon.