Expunge contacts on a shared folder. Log of who did it?

[alby87 at inwind.it]

Hi guys!

I've a little problem: there is a log of wich user deleted some content from a 
shared folder? I have some users with full ACL on a common address book, but 
today some contacts were missing. I need to know which user deleted this 
contacts (I've rescued them thank to the tutorial about backup and restore 
found in https://docs.kolab.org/administrator-guide/backup-and-restore.html

Thank you :)

Alberto