A disturbing video “manifesto” believed to be from the suspect in this week’s Minneapolis Catholic school shooting appears to show planning for the attack, police and media report. Authorities identified 23-year-old Robin Westman as the gunman who opened fire through church windows around 8:30 a.m. Wednesday during a back-to-school Mass.

Two children—an eight-year-old and a ten-year-old—were killed, and 17 others were injured, including 14 students and three elderly parishioners. Doctors confirmed several victims required emergency surgery.

Investigators said Westman previously attended the school and had been seen on campus days earlier. Court documents reveal that at 17, Westman legally changed names to reflect a female gender identity. Police Chief Brian O’Hara said Westman died at the scene from a self-inflicted gunshot.

Detectives are reviewing a video showing the suspect flipping through a journal and describing attack plans. BBC Verify reported the writings mention targeting “a large group of kids,” avoiding times when parents might be present.

O’Hara told the Today Show that all the injured are expected to survive. Support lines, including the 988 Suicide & Crisis Lifeline, have been shared.