Good words. I attended university with Atta many years ago and we remained (distant) friends since. He was a legend back then as a CS:S player and a BMW enthusiast, and pretty good at our regular "Quake Breaks" as well.
His company LWA Solutions, that was born out of LazyWorm Apps, did some work for the company I work for. Atta in particular was a driving force behind some of their really cool innovations - in VR. He was one of the first people I knew of who was using a tablet as a mock UI sketchbook, and producing some really cool work despite the awful capacitive touch pens of the time.
It's so difficult to reconcile his murder. He was such a genuine guy with so much ahead of him, and I'm so sorry for his family.