Delete a specific email using GAM

If a user send an inappropriate email to a loads of people or get stung by some sort of email exploit you can quickly delete the email from all of the recipients using a GAM command.

Step 1 - get the email header

Go into Google Vault and search for the offending user or someone known to have got the message.
Click show details and grab the email ID. This will be a long string of characters followed by @mail.gmail.com

Step 2 - find out who has the email

Go into Google Vault and find the original message sent by the offending user. Look at the details to see who got it. Copy the list and dump it into a spreadsheet. Clean up to just a list of emails with a column header 'mail'. Save as a csv file.

Step 3 - delete messages with GAM

Put your CSV file in your GAM folder - this e.g. assumes its called mail.csv
Run:
gam csv mail.csv gam user ~mail delete messages query rfc822msgid:MESSAGEIDHERE doit

The alternative nuke option is:
gam all users delete messages query rfc822msgid:MESSAGEIDHERE doit

The second option will try to delete the message for all users - but if you have a big domain it's much quicker to target affected users only. See here for more details. I've found this rather useful!