How to tell if one person has two gmail accounts

OK, so here’s the deal.

I run a fantasy baseball league. We had an owner leave and one of the existing owners - hereafter referred to as Player A - found a new guy to take over the team. Well and good.

However…

The new guy has a gmail account. When I type in his name, it autofills with the name of Player A.

We use googlegroups. Simple enough. I sent the new guy an invitation and it tells me that the new gmail address is a secondary or primary of an existing member of the group. It doesn’t say which one.

My co-commissioner - one hell of a guy - has known Player A since elementary school - 40 years ago. He was also best man at his wedding and so forth. This isn’t a casual relationship. Co-Commish called Player A who denies all, of course.

I have emails from both and wish to figure out if they’re coming from the same IP address. Is there a way to do so? Player A is using a hotmail account while the supposed newbie is using a gmail account.

What do you all think?

I’ve never seen a way to get the sender’s IP address from Gmail. There is a “Show Original” option but that doesn’t show the sender IP.

I would say you could embed a unique image URL in an e-mail to each member and study the webserver logs to find IP addresses in common, but Gmail has a new thing where they download images from e-mails themselves and serve them to you from their server.

Next best thing you could do if you are in control of a web server is send a unique URL to each person that they will likely/definitely click on. Then search the server logs for each retrieval of each unique URL and look for an IP that appears twice.

Set up a conference call to go over some rule changes you want to institute next season.