11:45 a.m. Thursday: At the school's first lunch period, a student threw a milk carton at another student. A minor scuffle followed.

12:30 p.m. At the school's third lunch period, rumors about what had happened during the first lunch period exploded into an all-out confrontation involving 200 to 300 students. About two dozen staff members tried to quell the violence, but could not. At least one was pushed and then fell to the floor.

12:41 p.m. Two police officers regularly stationed at the school called for backup. Eventually 10 additional police officers arrived. Some students threw objects at the staff and at the police officers. Two officers sprayed a chemical irritant dispersed from a handheld can above students' heads to force them out of the cafeteria. The students dispersed and the school was put on lockdown for the rest of the day.

Source: Minneapolis Police Department