EDINA, Minn. – Hennepin County authorities are investigating after an alleged assault left a teenager severely injured at a Twin Cities YMCA. According to a search warrant filed in district court Thursday, the alleged beating occurred on Dec. 11 just after 6 p.m. at a YMCA facility in Edina. Court documents allege officers responded to a call about a fight between several teens, who officers later determined had been let in through a back door by an unknown person.