Some federal search warrants have revealed new details about a shooting in August on the University of North Carolina's flagship campus that left a professor dead. The warrants state the graduate student charged in the shooting bought a pistol and also visited a gun range the day before Zijie Yan was killed inside a laboratory building at UNC-Chapel Hill. Tailei Qi was charged with murder and a gun-possession count but has been found unfit for trial due to likely schizophrenia. The shooting resulted in an hourslong campus lockdown and police manhunt that frightened students and faculty.