Police seized a dozen guns after the Monroe-area 20-year-old was arrested Friday in Lake Forest Park.

MONROE — On his YouTube page, the Monroe man borrowed the name Rudolf Höss, a commandant at Auschwitz.

For months, he used at least seven fake Facebook profiles to talk about shooting up a school or a synagogue, or “pulling a Dylan Roof,” according to police reports made public Monday. Dylann Roof was the gunman who murdered nine people in an African-American church in Charleston, South Carolina.

Dakota Reed, 20, was arrested Friday at his mother’s home in Lake Forest Park.

Snohomish County sheriff’s detectives and the FBI seized 12 firearms, ammo, gun magazines and handwritten notes “associated with white supremacy” from his home on High Bridge Road near Monroe.

He’s accused of making threats to carry out mass killings and violating Washington state’s hate crime law. Court papers make no link between Reed’s arrest and the racist beating of a DJ, hours later north of Lynnwood. In that case, eight people were booked into jail. Police say those suspects are “self-professed members of a neo-Nazi skinhead group.”

Unrelated posts by Reed on Facebook used pseudonyms. They were documented as early as October. Reed shared pictures of himself with three AR-15-style weapons, two hunting-style rifles, an AK-47-style rifle, a pump shotgun and at least one pistol, according to court papers. He posed with weapons while making Nazi salutes in a room full of white supremacy materials.

Posts referenced a line in Adolf Hitler’s autobiography about securing a future for white children. Shorthand for the phrase is code among today’s racist right. The slogan was popularized by The Order, a white hate group in the 1980s with roots in Washington state.

Reed’s posts professed a belief in a “Northwest Front,” a racist dream of a white nation-state in the Pacific Northwest. He shared a picture of a certificate saying he was a member of the Ku Klux Klan.

“I’m over here saving up to buy more guns and ammo to kill (((rats))) and animals,” read one of Reed’s posts, from Oct. 25. In dark corners of the internet, an “(((echo)))” symbol is an anti-Semitic code to identify people with Jewish backgrounds or ties.

Many other writings suggested an obsession with killing Jews.

“Six years until recleamtion (sic) day in the synogauge (sic),” read one post.

A day later, he wrote, “Tom stopped into the synogauge never to return.”

Tom was one of his alleged pseudonyms.

“Gonna make the news some more and shoot some Jews in 2025,” he posted on Nov. 24.

He wrote in early December about his parents asking why he owned military-style guns.

“To kill people,” he answered, according to his post. “Why else would I own them?”

The same day he posed the question on Facebook again. It was accompanied by a caricature of a Jewish man being executed.

In a video, Reed introduced himself as “Active shooter 327” and showed off a new sight on what he described as an AR-15. The video was captioned: “Rabbi: Please, don’t do this Tom.”

Dozens of Reed’s comments and photos were taken from a film about the Columbine High School shooting. On camera, he held the gun and said he was “fixing to shoot up a (expletive) school.” It was posted Dec. 4, 2018.

Snohomish County detectives were alerted Wednesday. FBI agents were aware of the violent threats for at least a month, according to court papers. Many posts were recently deleted, but it’s not clear who removed them.

Some pictures and videos posted online showed a home south of Monroe. Investigators identified Reed through those pictures and by linking the profiles to an associated phone number, email and home address.

The Snohomish County Violent Offender Task Force put Reed’s home under surveillance Friday but found he had gone to his mother’s apartment in King County. He was arrested without incident. He reportedly admitted to posts about shooting Jews and shooting up a school, and using fake names online. He gave police a combination for his gun safe at his home. His laptop was seized.

Reed claimed the posts were fictional and that he was “venting.”

Of the 12 guns, Reed claimed only five belonged to him, including a high-powered rifle.

A judge found probable cause to hold Reed in jail over the weekend. Bail was set at $50,000.

Everett District Court Judge Tam Bui delayed a follow-up hearing on Monday so a private attorney could argue bail.

The sheriff’s office filed paperwork in court Monday seeking an an extreme-risk protection order against Reed. That civil order prohibits someone from having access to firearms if they are considered a threat to themselves or others. More information about the filing was not immediately available.

In 2011, Reed, then 13, was convicted in Snohomish County juvenile court of reckless burning. He pleaded guilty, admitting to setting a dumpster fire at Lake Stevens High School. The case was deferred and then closed the next year. He left the Lake Stevens School District in 2012, transferring to Marysville.

Reporter Rikki King contributed to this story.

Caleb Hutton: 425-339-3454; chutton@heraldnet.com. Twitter: @snocaleb.

This story has been updated to show Dakota Reed left the Lake Stevens School District in 2012, transferring to Marysville.