In the days since a shooter killed two children and wounded 18 people gathered for Mass in Minneapolis, authorities have combed through a trove of evidence to uncover a potential motive for the tragedy.

Records show that investigators have combed through writings and online posts, searched residences in the area tied to the shooter and conducted interviews, court records newly obtained by the St. Cloud Times, part of the USA TODAY Network, show. In the records, investigators described the blood-soaked scene inside Annunciation Catholic Church on Aug. 27 after 23-year-old Robin Westman sprayed pews with bullets through stained-glass windows from outside the building.

Over 100 bullet casings were found at the scene. An AR-15-style rifle, a 12-gauge shotgun and a 9mm pistol were all found with additional ammunition on the suspect's body. Westman died of a self-inflicted gunshot wound, authorities said.

As investigators continued to probe a potential motive, the Minneapolis community mourned the shattering losses of 8-year-old Fletcher Merkel and 10-year-old Harper Moyski, both killed in the attack. Of those injured, 15 were children and three were parishioners in their 80s, officials have said. In a news conference on Aug. 29, Minneapolis leaders praised the schoolchildren and staff at Annunciation that day for their actions as shots rang out.

"They jumped on the backs of their closest friends to make sure that they were protected from bullets and they escorted students out of the way to make sure they weren't hit by fire. They're heroes," Mayor Jacob Frey said.

What investigators found at the scene of the shooting

Search warrant affidavits obtained by the St. Cloud Times detail what items investigators found at the church after the shooting and what they were hoping to find in extensive searches of area residences tied to the shooter.

Westman was found dead at the back of the church, wearing black "tactical gear" including a mask, according to police affidavits. Police also found ammunition, a 2x4 wood board with what appeared to be smoke canisters affixed to it and a belt of magazine pouches around the suspect's body.

Officials have said a regular church practice of locking doors after Mass began probably saved lives, and that Westman tried to barricade a door from the outside to prevent people from exiting.

Inside the church, police found "blood and other biological evidence in multiple areas of the church." The two children who died were found inside the pews, the affidavits show.

The warrants show investigators were looking for firearms, explosive materials, ammo and financial records indicating how Westman obtained weapons, plus items that could help them narrow down a motive including cell phones, laptops, memory cards and any written documents, including "notes referencing planning, motive, targets, ideology, or grievances."

Father of shooting victim speaks out

Jesse Merkel, the father of Fletcher Merkel, urged other parents to give their children "an extra hug and kiss" in a public statement.

Fletcher "loved his family, friends, fishing, cooking, and any sport that he was allowed to play," his father said standing outside Annunciation on Aug. 28.

"While the hole in our hearts and lives will never be filled, I hope that in time our family can find healing," Jesse Merkel said, calling the shooter a "coward."

Minneapolis adding extra patrols at schools, churches

Officials said on Aug. 29 that Minneapolis police and officers from other jurisdictions were stepping up patrols at locations including houses of worship and schools through at least Sept. 5.

"We know that our Minneapolis police officers experienced some pretty significant trauma in what they saw and what they had to do on Wednesday," Frey said, adding that officers were being given the necessary time to rest and recover while receiving assistance from neighboring departments.

Survivors, witnesses and neighbors have access to funds to reimburse for things like lost wages, medical expenses, childcare and others while they recover, officials said.

"We've learned through this challenge that we are a very resilient community. We're a community of people who care about one another. And unfortunately through these incidents, it tells us time and time again that Minneapolis remains strong," Minneapolis Police Department Assistant Chief Christopher Gaiters said.

Contributing: Michael Loria, Corey Schmidt and Melina Khan

This article originally appeared on USA TODAY: Records reveal what weapons Minneapolis shooter had. What we know about the investigation

Reporting by Jeanine Santucci, USA TODAY / USA TODAY

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