Updated 5 a.m. Thursday:
A University of Arizona professor has been shot and killed on campus by a former student, who has since been arrested.
Authorities say Arizona state troopers stopped 46-year-old Murad Dervish roughly 120 miles away from the Tucson campus, just hours after Wednesday's shooting.
University of Arizona Police Chief Paula Balafas says the shooting happened shortly after 2 p.m. when someone called 9-1-1 requesting a police escort for a former student.
The only victim wounded was later pronounced dead at the hospital. Balafas confirmed he was a hydrology professor.
She did not know about the history between the victim and the shooter. Classes were canceled, but they will resume Thursday.