The youngest shooting victim in King County over the past five years was killed yesterday in a Skyway shootout.Investigators recovered more than 20 shells from the parking lot of the Cedar Grove apartments, where detectives said two groups were arguing around 6 p.m. The 12-year-old victim reportedly ran a block to a nearby 7-Eleven after being shot before he collapsed and died.Sgt. John Urquhart of the King County Sheriff’s Office says that a man in his 20s was also wounded and flown to Harborview. He’s still in critical condition today.According to Urquhart, the boy didn’t live in the apartment building. Nor was he the intended target. No arrests have been made.