Norman police have arrested four people in Sunday's fatal shooting of 20-year-old Nathan Ewing, an OU student who was gunned down in the parking lot of the Willowbrook Apartments on east Lindsey Street. Police arrested two 17-year-old males, 20-year-old Tyrek Turner and 19-year-old Armani Morgan. All four were booked into the Cleveland County Detention Center on first-degree murder complaints. Police say the shooting remains under investigation.