A tragic attack occurred at Annunciation Catholic Church in Minnesota. The attack happened during a special Mass for the start of the new school year.
The violent event left two children dead and 18 others injured. The community was shocked by this sudden violence.
Police investigators are now working to understand why this happened. They are looking at the shooter's life and background.
The investigators found writings and videos from the shooter. This information shows that the shooter had violent thoughts and ideas for a long time.