He entered the building sometime at 4 p.m. on December 6, 1989 with a Ruger Mini-14 rifle and Hunting knife.
After he entered a second floor mechanical engineering class of about sixty students at about 5:10 p.m., he approached a student that was giving a presentation.
He ordered that everyone stop what they were doing and both men and women to go to opposite sides of the classroom.
Nobody moved at first, believing it to be a joke until he fired a shot into the ceiling.
He killed six women and wounded three others there.

After that, he moved to the second floor corridor and wounded three other students before he entered another room where he tried to shoot a female student twice but failed.
He reloaded the gun in the emergency staircase and tried to enter the room that he left but the students locked the door.
He attempted to unlock it with three gunshots but failed.
He moved through the corridor where he shot wounded a student.
He went to the financial services office and shot and killed a woman through the window of a door she had locked.

He went down the stairs to the first floor cafeteria which had around a hundred people in it.
He shot a woman standing near the kitchens and wounded another student.
After hearing the gunshots, everyone scattered.
He killed two more women after finding them hiding.

He went up the escalator to the third floor shooting and wounding three students in the corridor.
After entering a classroom where a presentation was being held, he shot at the front row and killed two women who were trying to escape.
He shot three more female students and killed another.
After hearing Maryse Leclair, a student he had shot, ask for help, he took out his hunting knife and stabbed her three times, killing her.
He then took off his hat, wrapped his jacket around the gun, said "Ah shit," and then killed himself.
He entered the building sometime at 4 p.m. on December 6, 1989 with a Ruger Mini-14 rifle and Hunting knife. After he entered a second floor mechanical engineering class of about sixty students at about 5:10 p.m., he approached a student that was giving a presentation. He ordered that everyone stop what they were doing and both men and women to go to opposite sides of the classroom. Nobody moved at first, believing it to be a joke until he fired a shot into the ceiling. He killed six women and wounded three others there.
After that, he moved to the second floor corridor and wounded three other students before he entered another room where he tried to shoot a female student twice but failed. He reloaded the gun in the emergency staircase and tried to enter the room that he left but the students locked the door. He attempted to unlock it with three gunshots but failed. He moved through the corridor where he shot wounded a student. He went to the financial services office and shot and killed a woman through the window of a door she had locked.
He went down the stairs to the first floor cafeteria which had around a hundred people in it. He shot a woman standing near the kitchens and wounded another student. After hearing the gunshots, everyone scattered. He killed two more women after finding them hiding. 
He went up the escalator to the third floor shooting and wounding three students in the corridor. After entering a classroom where a presentation was being held, he shot at the front row and killed two women who were trying to escape. He shot three more female students and killed another. After hearing Maryse Leclair, a student he had shot, ask for help, he took out his hunting knife and stabbed her three times, killing her. He then took off his hat, wrapped his jacket around the gun, said "Ah shit," and then killed himself.
École Polytechnique massacre