The writings left behind by the shooter in Wednesday's deadly attack at a Minnesota church have many of the underpinnings of a troubled person - and leave just as much confusion over why the mass shooting occurred.

The suspect, Robin Westman, 23, appears to have posted at least two videos on YouTube. The first showed a multiple-page document written in English but in Cyrillic characters. The second showed a four-page document in which the shooter apologizes to family and friends and writes about feeling pain and suffering.

The rest of the video shows the shooter displaying an arsenal of weapons including a rifle, a handgun, a shotgun and several magazines of ammunition, scrawled on with a mishmash of political messages and in-jokes.

Authorities say the cryptic writings are at the forefront of a domestic terror investigation into Westman and what FBI Director Kash Patel said was anti-Catholic attack that killed two children and injured 17 others during a Catholic school Mass before committing suicide in the rear of the church.

But like with many mass shooters, Westman's motives - even with the detailed writings - will be hard to decipher into anything meaningful that could prevent future attacks. Westman is believed to have been a former student at the Annunciation Church and Catholic School in Minneapolis, but authorities say it's unclear what role that may have played.

There are clues the shooter was active in hateful online communities. The word “Skibidi” was written on one magazine of ammunition found at the scene of the attack, a possible reference to a short-lived online extremist message board taken down a few weeks ago.

The writings also reference two other mass shooters. The name “Rupnow” is written on a rifle, a possible reference to Natalie Rupnow, who killed three students at the Abundant Life Christian School in Madison, Wisconsin, last December and injured six others, and “Breivik,” an apparent reference to Anders Breivik, who killed 77 people in an attack in Norway in 2011.

"It's very early to fully assess what may have brought about this horrific violence," said Rachel Carroll-Rivas, interim director of the Intelligence Project at the Southern Poverty Law Center. "But early indications show a young person expressing a mix of ideologies, politics and inspirations. It may not fit neatly in a box."

Minneapolis police and other law enforcement agencies responded to the scene of a shooting near Annunciation Church and Catholic School in Minneapolis on Aug. 27.

A mixture of hate, directed at several groups

Public records show Westman's last known address was an apartment in the city's South St. Paul neighborhood.

Court records show Mary Westman, the mother of the suspected shooter, signed a petition to change her child's name in 2019. A handwritten filing said the "minor child identifies as a female and wants her name to reflect that identification." A district judge approved the change in 2020 when Robin Westman was 17.

An analysis from the Anti-Defamation League noted that Westman's writings contain clear antisemitic messages as well as other racist content targeting Christians, Jews, Black people, LGBTQ+ individuals, Muslims and Hispanics.

In a post on social media, U.S. Homeland Security Secretary Kristi Noem said the shooter had the words "‘For the Children’ and ‘Where is your God?’ and ‘Kill Donald Trump’ on a rifle magazine."

"This level of violence is unthinkable. Our deepest prayers are with the children, parents, families, educators, and Christians everywhere," Noem wrote. "We mourn with them, we pray for healing, and we will never forget them."

Officials believe the shooter used three legally purchased firearms − a rifle, a shotgun and a pistol − and fired from outside the building through the church's windows.

A video, a handwritten journal and an arsenal of firearms

Police officials referenced online messages from Westman released Aug. 27 that were timed to publish during the shooting. Minneapolis Police Chief Brian O'Hara said the FBI ordered the YouTube clips to be taken down and was reviewing them for a possible motive, but USA TODAY was able to review archived postings.

Archived versions of the videos from the now-deleted YouTube page show the shooter displaying a handwritten journal and a cache of weapons.

The videos included a handwritten map of the interior of Annunciation Church. Westman's firearms were marked with a variety of political slogans in silver marker in both English and Russian.

FBI Director Patel said the attack is being investigated as "an act of domestic terrorism and hate crime targeting Catholics.''

Where is Annunciation Church and Catholic School?

The school is at 525 W 54th St. in Minnesota, about six miles south of downtown near the city's Windom neighborhood, about four miles northeast of the Minneapolis-Saint Paul International Airport.

What happened in the Minnesota Catholic school shooting?

The shooting took place about 8:30 a.m. at the church, which also has a school on site, Police Chief O'Hara said.

According to a preliminary investigation, O'Hara said the shooter approached the church building from the outside and fired inside toward children sitting in pews.

The Mass was in celebration of the first week of school, O'Hara said.

The children were worshiping God when gunfire rang out.

"Teachers were beginning a new school year. Families were entrusting their loved ones to the care of the church," Bishop of the Diocese of Saint Cloud Patrick M. Neary told USA TODAY. "I grieve with every person who now carries the trauma of this senseless violence. As Catholics, we believe in the dignity of every human life. That dignity is destroyed."

Who died in the Catholic school shooting?

Police reported that two children, an 8-year-old and a 10-year-old, died in the shooting.

Fourteen of the 17 people injured were children and two of those children were in critical condition, O'Hara said.

O'Hara said three church parishioners, in their 80s, were hit by gunfire and were being treated.

Information about the extent of their injuries was not immediately released by law enforcement.

It was not immediately known whether any police officers suffered injuries in the shooting.

This story was updated to add additional information.

Contributing: Jeanine Santucci and Corey Schmidt

Natalie Neysa Alund is a senior reporter for USA TODAY. Reach her at nalund@usatoday.com and follow her on X @nataliealund.

This article originally appeared on USA TODAY: What we know about Minneapolis shooting suspect Robin Westman

Reporting by Will Carless, Nick Penzenstadler and Natalie Neysa Alund, USA TODAY / USA TODAY

USA TODAY Network via Reuters Connect