Killer Deathgrind band from the Seattle area featuring members from Black Breath, Splatterhouse, etc - a band that seems to fly under the radar for some reason, definitely check them out.
This longsleeve is from their Regression album that came out back in 2015. I am pretty sure I ordered it from whatever website they had merch on at the time, maybe shirtkiller.com or something similar. The front is a mirror image skull businessman shooting up with the sleeves reading ‘Regression’ and ‘Theories’ so very straightforward. Cool album, good quality shirt that’s stood up to much wear and tear for several years.