Hi @Anonymous
According to this official document, Teams chats messages can be deleted by using retention policies for Teams, so for your requirement, you can consider creating a retention policy to permanently delete Teams chats messages for this user:
- Go to Microsoft Purview compliance portal, select Data lifecycle management > Retention Policies.
- Select + New retention policy to start the Create retention policy configuration, and name your new retention policy.
- Choose Static, Teams chats, specify the user you want to include:
- For Decide if you want to retain content, delete it, or both page, specify the configuration options for deleting content:
- Complete the configuration, review and save your settings.
More details, you may refer to: Retention policy for Teams locations.
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