RICHMOND, Va. (AP) – Virginia Tech said a police officer was shot Thursday and a possible second victim was reported at a parking lot near the campus, where 33 people died in 2007 in the deadliest mass shooting in modern U.S. history

A campus-wide alert told students and faculty to stay inside and lock doors. Authorities were seeking a suspect.

A law enforcement official, who spoke on condition of anonymity because he was not authorized to discuss the case, said initial reports indicated that the shooting occurred following a traffic stop.

The suspect was described as a white male wearing gray sweat pants, a gray hat with neon green brim, a maroon hoodie and backpack.

A message left with the university wasn’t immediately returned. Campus police referred all questions to the university.

The shooting came the same day as Virginia Tech was appealing a $55,000 fine by the U.S. Education Department in connection with the university’s response to the 2007 rampage, when a student gunman killed 32 students and faculty and then shot himself.

A report of a possible gunman at Virginia Tech on Aug. 4 set off the longest, most extensive lockdown and search on campus since the 2007 bloodbath led the university to overhaul its emergency procedures. No gunman was found, and the school gave the all-clear about five hours after sirens began wailing and students and staff members started receiving warnings by phone, email and text message to lock themselves indoors. Alerts were also posted on the university’s website and Twitter accounts.

The emergency was triggered by three teens who were attending a summer program on campus and told police they saw a man walking quickly across the grounds with what might have been a handgun covered by a cloth, authorities said.

Police searched some 150 buildings on the square-mile campus and issued a composite sketch of a baby-faced man who was said to be wearing shorts and sandals, but they found no sign of him. They continued to patrol the grounds as a precaution even after the lockdown was lifted.

“We’re in a new era. Obviously this campus experienced something pretty terrible four years ago,” Virginia Tech spokesman Larry Hincker said at the time. “Regardless of what your intuition and your experience as a public safety officer tells you, you are really forced to issue an alert.”

That incident marked the first time the entire campus was locked down since the 2007 shooting, and the second major test of Virginia Tech’s improved emergency alert system. The system was revamped to add the use of text messages and other means besides email of warning students.

The system was also put to the test in 2008, when an exploding nail gun cartridge was mistaken for gunfire. But only one dorm was locked down during that emergency, and it reopened two hours later.

Eric Tucker in Washington contributed to this report.