[atc23]

Shooter has an antifa tattoo on right arm

[LegendHasIt]

Yep. I knew we could count on the maniacs at 4Chan to figure things out:

This page shows the image on a Czechoslovakian Antifa website: (It is one of several space invaders images that are part of some Antifa identification code)
https://www.antifa.cz/content/rozhovor-s-rosa-antifa-wien