Complete Email Header Information

Someone hacked a website I had an account with and got my gmail email address and password to the website (different from my email password, which I immediately changed to random and made twice as long). My leaked email account is the one registered with this web site.
He is sending me threatening spam and is asking for money. I want to send him to the ic3 but I need complete header path information. I suspect he is located in Asia.
Now, he is likely be hiding it and/or I may be unschooled at bringing it up. With cases like this I have brought gmail headers up in the past. My problem is: I have four platforms and online help pages talk about down arrows and menu clicks and, because of versions, none of that appears on my platforms as described. Also, multiple help sites just seem to copy each other. Can someone actively help me uncover his header in gmail?
I have: 8 yr old Toshiba E205-S1904 running Windows 7 Home Premium Service Pack 1; and 3 Mobiles: Chinese LeS3 mod. Le X522, Android 6.0.1, Galaxy S9+ mod. SM-G965U1, Android 8.0.0, iPhone6S running iOS 11.4. I am traveling extensively for the year and I am currently in Myanmar using prepaid data packages on local telnet sim cards.

 

Open the message in Gmail in a web browser. Click the More button - the button with three vertical dots near top right - and on the flyout menu click Show Original. That's it. You may need to change your email addy to stop further messages unless you can create an effective filter.

 

Found the problem.
"Show Original" does not show up on the gmail More button on any of the platforms when using Firefox.
It finally showed up when using Chrome.
Some of us do not like Google and do not like Chrome, but other browsers seem to be denied full support of gmail.
This took me an hour of trial and error.
No one said to use Chrome, but now I know.
Thank you.

 

It shows up on all systems here. They all use Firefox 66.0.3 64 bit

 

If you need this again I suggest you start Firefox with addons disabled (it's in the Help menu)

 

Don't click on the More button.
Click on the 3 dots lower and to the right. This only shows after you have a message open.
The options are: (FF ESR v 60.6 and Palemoon tested) I did not need to disable any of my addons.
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