A Mankato police officer said he got a phone call about 1 a.m. Tuesday from an old high school friend.

The man on the other end of the line was Allen Lawrence “Lance” Scarsella III, who confessed that just two hours before he had shot five people at a protest outside the Minneapolis Police Department’s Fourth Precinct station, according to court documents.

Hours later, authorities raided Scarsella’s Bloomington home, seizing a dozen weapons and making the first of five arrests in connection with the shooting, which heightened racial tensions in the aftermath of 24-year-old Jamar Clark’s fatal shooting during a struggle with police.

New details of the hours following the shooting of Black Lives Matter protesters were revealed in an application for a search warrant filed Wednesday in Hennepin County District Court.

Prosecutors said Wednesday afternoon that they will need more time to decide if charges will be filed against the four men still being held in connection with the shooting.

In the warrant, Scarsella, who is white, tells the officer, identified only as “Levin,” that he and some friends had gone to the Black Lives Matter protest to live-stream it and that they had an altercation with protesters, leading to the shooting. The Mankato officer told Minneapolis police that Scarsella owns a .45-caliber weapon, matching the size of the eight shells found at the shooting scene.

Employees of Estes Funeral Chapel raised their fists to show support for Jamar Clark's family in front of the Fourth Precinct police station November 25, 2015, in Minneapolis.

In a search of Scarsella’s home, police found computer equipment, cellphones, camouflage clothing, an AR-15 rifle, bolt-action rifles, revolvers and ammunition. The search warrant also revealed that police were looking for white supremacist paraphernalia.

He remains in the Hennepin County jail, along with Nathan Gustavsson, 21, of Hermantown, Minn., and Daniel Macey, 26, of Pine City, Minn., who turned themselves in. On Wednesday, police also announced the arrest of Joseph Martin Backman, 27, of Minneapolis, on suspicion of assault.

A 32-year-old Hispanic man arrested in south Minneapolis Tuesday was later released because, police said, he was not at the shooting.

Police said they aren’t seeking any more suspects. Authorities are weighing whether to treat Monday’s shooting as a hate crime, according to sources familiar with the investigation.

Online connections

At least some of the men arrested in connection with the shooting had shown up at the Black Lives Matter protests more than once.

When about a dozen protesters attempted to herd the men away from the scene on Monday, witnesses said, the gunfire began and five protesters were hit. The victims — all black men ages 19 through 43 — were taken to hospitals. Their injuries were not life-threatening.

In a subsequent incident early Wednesday morning, police responded to a “shots fired” activation from the city’s ShotSpotter equipment in the area near the Fourth Precinct station.

The 12:40 a.m. report came from near the 1300 blocks of Newton and Morgan avenues N. No one was injured; suspects were stopped and identified by officers and one man was booked into jail. His name had not yet been released. A police department spokesman said he didn’t know if the shots were related to the protest.

Hennepin County Attorney Mike Freeman said the deadline extension for charges will expire at noon Monday.

The four men appear to have become acquainted in school and at meetups through “/k/,” a popular weapons-related message board with racist overtones on the website 4chan.

Gustavsson, who is white, and Macey, who is Asian, both are students in the gunsmithing and firearms technology program at Pine Technical and Community College. Gustavsson has been enrolled there since 2012; Macey signed up in the fall of 2014.

Records show that Scarsella, a 2010 Lakeville North High School graduate and Eagle Scout, graduated from the University of St. Thomas in 2015 with a bachelor of arts degree.

Reached at her home outside San Antonio, Scarsella’s grandmother, Enriqueta Scarsella, said she was not aware that he had been arrested.

“Oh, my gosh! Lance is a good boy — my oldest grandson,” she said, adding that she wasn’t aware of allegations that he could be involved in a racial confrontation.

“Oh, no, he had all kinds of friends in school,” she said.

At the funeral procession for Jamar Clark at the Police 4th Precinct, family members got out of the limousine to show support for the Black Lives Matter supporters.

Videos of suspects surface

Scarsella, Gustavsson and Macey, along with the man who was questioned and released, are featured in several videos of a now-deleted YouTube page. The page’s banner featured two dozen men — some masked — holding weapons, along with a pair of Confederate flags. The videos were deleted by Monday afternoon, but they had been archived by Minneapolis-based researcher Tony Webster.

Another video emerged as part of a live stream filmed at the protests Friday by the man known as “SaigaMarine,” who was later questioned and released by police.

“If I get in trouble for yelling ‘master race,’ there’s only one final solution,” he said in the video.

A masked man accompanying him who resembles Scarsella then enters the frame and joins protesters dancing to a hip-hop song.

“Oh, my God, he’s gonna die, guys. He’s been culturally enriched,” the man filming says. “I can’t do anything for him. I’m going to have to shoot him.”

Staff writers Pat Pheifer and Liz Sawyer contributed to this report. david.chanen@startribune.com 612-673-4465

abby.simons@startribune.com 651-925-5043