The violence sparked a campuswide lockdown during the search for a graduate student, who remains locked up and charged with the crime.
UNC is preparing to honor the man gunned down with a bell tower tribute Wednesday.
Tailei Qi was arrested and charged in the shooting of his professor Dr. Zijie Yan. Documents showed they were overheard arguing before five gunshots rang out inside Caudill Laboratories about 1 p.m.
The 9mm handgun that authorities say was used in the deadly shooting has not been found.
Yan was an associate professor in the Department of Applied Physical Sciences in the College of Arts and Sciences who had worked for the university since 2019. At a vigil the day after the shooting, Yan was remembered as "a wonderful human being" and a talented scientist.
'Wonderful human being': Colleagues remember UNC professor Zijie Yan who was killed in shooting