This comes from Search Engine Roundtable who got it from this Google Groups thread.
1. Your full name and contact information, including a verifiable email address.
2. The Gmail address of the individual who passed away.
3a. The full header from an email message that you have received at your verifiable email address, from the Gmail account in question. (To obtain the header from a message in Gmail, open the message, click ‘More options,’ then click ‘Show original.’ Copy everything from ‘Delivered- To:’ through the ‘References:’ line. To obtain headers from other webmail or email providers, please refer to http://www.spamcop.com/help_with_headers/)
3b. The entire contents of the message.
4. A copy of the death certificate of the deceased.
5. A copy of the document that gives you Power of Attorney over the Gmail account.
6. If you are the parent of the individual, please send us a copy of the Birth Certificate if the Gmail account owner was under the age of 18. In this case, Power of Attorney is not required.
