1. Login to your Admin Console (https://admin.google.com)
2. Click Reports > Audit > Email Log Search
3. Input the Sender Email/Recipient Email/Message-ID (from Gmail Full Message Header) for a more accurate result.
4. Take a Screenshot for the Result
5. Click one of the Results for details, screenshot again with expanding all the "Right arrow" fullscreen (without the cut).
Reference for G Suite Email Log Search in this link:
https://support.google.com/a/answer/2618874?hl=en