Freshman Juliette Fielding came upon the officer's shooting moments after the gunman fled.
"I was coming out of the gym and just walking on the sidewalk to go home to my dorm. I saw the police car sitting there and I thought it was responding to a call here," Fielding said.
She walked toward the car, thinking she could go around it before other police cars arrived.
"The police pulled up and they opened his car door and as soon as they opened it, he just fell out toward the ground," Fielding said through tears.
Fielding said the officer's face was covered in blood and the other cops immediately began efforts to revive him.
Fall term final exams that were originally scheduled to begin today will start Saturday instead, school officials said.
ABC News Radio and The Associated Press contributed to this report.