A 20-year-old Auburn man waived his first court appearance Tuesday when a King County District Court judge found probable cause to hold him on investigation of second-degree murder for allegedly shooting a Lake City taproom employee in the back of the head during an after-hours hangout. The man who was killed, Quusaa “Q” Margarsa, 25, had closed up The Growler Guys in the 8500 block of Lake City Way Northeast on Friday night before returning to the business hours later. He was accompanied by a man — who police determined to be the suspect — and a woman he met at a hookah lounge on Aurora Avenue North, according to the probable cause statement outlining the police case against the 20-year-old. Defense attorney Pete Mazzone argued the shooting “is a clear case of self-defense” and noted his client doesn’t have significant criminal history, is employed at Boeing, has “stable parents” and turned himself in to police.…