So already you can tell that there's someone out there who has a weird obsession with the number 8, and who has made the genius observation that 8 looks like a sideways infinity symbol, so we're obviously dealing with someone whose powers of deduction are second to none.
But the important thing is the crude diagram that is scribbled next to most of Abrahams' graffiti messages:
You can actually find a location on the map that matches up with this image:
Just look for the peninsula that's shaped ominously like someone waving their dick.
And if you dive under the water and look around, you can actually locate the eight victims of the "Infinity 8 Killer" that the authorities were never able to find.
"Sorry, we were busy hunting the 'ALL YOU ASSHOLES THAT PLAY THIS GAME KILLER'."
Given that your character kills more people than this guy in the course of driving between mission objectives, there's really no reason to go to the cops with this information, but it's pretty spooky all the same.