Already spoke about this on the CSv Mumble server, but thought I'd post here since it's here.
His name is beekh1946 (steam page).
I was a spy, moving invisibly in an area far enough from enemy teammates to not be revealed, and he was regularly getting really good headshots on me when there was no way he should have. I called him out and he said something snarky like "lol report me faggot."