Badmins is a Facebook group. I'm on Facebook but frankly don't know much about how it works. Do you need to have a Facebook profile to read things on Facebook?
I'm sure he has an online history. What he apparently doesn't have is an online presence, which I take to mean that he doesn't have a profile in any SM platform. But he was apparently accessing the Badmins site somehow, if RO is accurate.
If he was accessing info from, say, his mom's computer , isn't it likely that her FB password was stored and he just logged in as her?
Or any other family member if he " visited" anyone that often, which I really doubt.
Years ago, and maybe now, it was possible to create a FB account with truthful info, and simply use it to read the trending FB posts or maybe to look up a specific page, like " Find Jayme" page or something.
At the end of the browsing session, there's an option in SETTINGS to DEACTIVATE the account. Facebook said this means it's like it doesn't exist but isn't the same as a permanent deletion of an account.
What this allowed someone to do if they weren't supposed to have a SM presence for security reasons was to see Facebook- specific content that may have been extremely important to them personally.
I'm one of those people who shouldn't have a Facebook or any other SM accounts for security reasons and I used the method until I realized there's NOTHING I need to know badly enough to jeopardize my personal safety. I could have been online at the same time as the man who abducted me was, and sometimes, the privacy settings didn't work like they were supposed to.
( Almost everyone knows about the privacy security flaws now, but it was easy to check years ago).
So, he may have " used" another person's Facebook account if could with a computer- specific saved password, or set up his own account at some point in time and kept it in Deactivated status unless HE wanted info from a business on FB.