Office 365 forensic

The most straightforward thing to do would be to speak to an O365 Admin at the company in question and get them to produce the data for you from the Security and Compliance Centre from within O365.

The built in e-Discovery tool is extremely powerful across large scale enterprise.

From within the Security and Compliance Centre your Admins should have access to the UAL (unified audit log) to produce any log files you require to prove file access, folder access, times and dates, deletions etc.

Check out this link to Microsoft's support pages where you can find loads of good information

Microsoft O365 Support - Manage e-Discovery Cases

thank you very much. It's great

You're welcome. )

My former colleague Adam Harrison has published some decent research into this very area

https://blog.1234n6.com/2018/07/investigating-office365-account_12.html

thanks