A judge has ordered the teenager accused in the shooting of 11-year-old Shamiya Adams on Chicago's South Side held without bond.
Police say 18-year-old Tevin Lee tried to shoot a rival gang member, but missed.
Chicago Police Superintendent Garry McCarthy said police arrested Lee on Tuesday, but the charges, including murder, did not come down until late Wednesday.
Lee is a known gang member, and police are confident he is the one who pulled the trigger.
Shamiya was killed by a stray bullet that went through the window of an East Garfield Park apartment building last Friday while she was at a slumber party.
Police say it all started Friday afternoon when two 14-year-olds got into a fistfight, and one of Lee's friend lost; about six or seven hours later, police say Lee returned, thought he saw rival gang members involved in that fight, and opened fire in retaliation.
One of the bullets hit Shamiya in the head.