Retention policy on Office 365 Group conversation

[DouglasHamilton]

Hi!
have created a retention policy retaining content forever and included All Office 365 Groups. Upon deleting documents in the corresponding SP Team Sites, they are stored in the Preservation Hold Library as expected. But Group members are still able to delete conversations and when they do I have no idea where conversation messages go or how to recover them. 

According to the documentation, retention policy are supposed to include conversations as well as they are stored in the shared mailbox of the group. 
https://docs.microsoft.com/en-us/office365/securitycompliance/retention-policies

Did I misunderstood how retention policies work on Groups?
Thanks in advance,
Douglas

[#2]

Deleted conversation simply go to a "hidden" folder in the Group mailbox that cannot be accessed by end users. The process is detailed here: https://docs.microsoft.com/en-us/exchange/policy-and-compliance/recoverable-items-folder/recoverable...

[#3]

Thanks for your reply. I'm afraid I don't know how to find this "hidden" folder. As an admin I'm able to open the Office 365 Group shared mailbox but the Deleted Items folder is empty despite the retention policy. If i click Recover deleted items I get the message "We didn't find anything to show here."

Am I looking at the wrong place?

Thanks, Douglas

[#4]

Search and recover these items via e-discovery:

https://docs.microsoft.com/en-us/office365/enterprise/recover-deleted-items-in-a-mailbox

[#5 · Accepted solution]

Recovering items is a different story, as in general we don't have any supported way to access any folder in the Group mailbox, apart from Inbox. Thus you will have to either use eDiscovery or some EWS-based script such as the one here: https://blogs.technet.microsoft.com/exovoice/2017/04/26/recover-deleted-items-from-a-group-mailbox-i...

[#6]

Thank you Adam and Vasil for your input. eDiscovery Search turned out to be exactly what I was looking for.