A law enforcement investigation report on a deadly shooting at a small-town Iowa high school in January reveals new details of the shooting, including that the teenage shooter attempted to livestream his actions.

The town of Perry, located about 40 miles (65 kilometers) northwest of Des Moines, was rocked when 17-year-old Perry High School student Dylan Butler opened fire on students and staff before the start of classes on Jan. 4, the first day of school following the winter break. Butler took his own life with a single gunshot minutes after he began shooting.

The shooting occurred in the school’s commons area, where about 50 students and staff had gathered for breakfast before classes. According to the report, Butler arrived at the school at 7:12 a.m. with a shotgun, revolver, knife and homemade explosive device concealed on him and immediately went to a bathroom near the commons area. While in the restroom, Butler posted on social media and began livestreaming, the report said without detailing the nature of the posts or livestreaming content.

He emerged 23 minutes later wielding the shotgun and began firing. Within the first 24 seconds, Butler fatally shot 11-year-old sixth-grader Ahmir Jolliff and wounded four other students and Perry High School Principal Dan Marburger, the report said.

The report, written by the Dallas County Attorney’s Office and a summation of investigations by several agencies, carries a warning to readers of the disturbing details in it. The report also confirms the heroic actions of Marburger and others to intervene, detailing how the principal and Assistant Principal Brad Snowgren moved towards the source of the gunfire when it began.

Snowgren triggered an alarm informing first responders of an active shooting at the school 10 seconds after the first shot was fired and 25 seconds before the first 911 call, the report said. The first police officer entered the school in less than two minutes. Officials had initially reported that law enforcement entered the school in “less than seven minutes.”

The report says Marburger, who was wounded seconds into the shooting, had a chance to escape the building but remained inside and pleaded with Butler to stop shooting. More than a minute later, the wounded Marburger again confronted Butler. Butler responded by shooting and critically injuring Marburger, who then left through an exit. Marburger died days later at a Des Moines hospital from his injuries.

Dallas County Attorney Jeannine Ritchie said her office has concluded Butler acted alone and the investigation found no evidence that anyone had specific knowledge of Butler’s plans or helped him in the shooting. Investigators also have not determined how or where Butler got the shotgun he used, but said evidence suggests it came from “outside his home and was taken without the owner’s permission or knowledge.”

“The evidence suggests his actions that morning were indiscriminate and driven by a desire to commit suicide with the hostile intent of taking others with him,” Ritchie wrote.