On Snapchat, Dayton Sauke bragged about his illegal "sawn-off" shotgun and his plans to kill a law enforcement officer at a pro-Trump rally at the Minnesota Capitol last weekend.

"Even if I kill only 1 cop thats more than antifa cop lovers have ever killed," the 22-year-old Owatonna man boasted under a photo of himself smoking a cigarette.

On Friday, the federal agents who had been monitoring Sauke's social media arrested him after Sauke sold an illegal firearm to two undercover agents from the Bureau of Alcohol, Tobacco, Firearms and Explosives, according to federal charges filed Tuesday. Sauke made his first appearance on the felony charge on Tuesday and will remain in custody until his next hearing later this week.

Since the Jan. 6 attack on the U.S. Capitol, federal law enforcement has bolstered efforts to find and stop violent extremists across the country leading up to the inauguration of President-elect Joe Biden on Wednesday. The Minnesota Capitol has gone into a state of lockdown, heavily guarded this past weekend in response to plans of armed protests that never materialized. A bulletin from the FBI's Minneapolis field office warned of credible attacks from members of the anti-government Boogaloo Bois, a group intent on starting a civil war.

Federal sources with knowledge of the case say Sauke appears to be a lone wolf, not tied to any network of extremists. But many of his social media posts reflect an anarchistic ideology similar to the Boogaloo Bois. One social media photo shows Sauke carrying a gun along with the caption "Sic Semper Tyrannis," a Latin phrase co-opted by the Boogaloo movement meaning justice will befall tyrants — the same words uttered by Abraham Lincoln's assassin and that appeared on Timothy McVeigh's T-shirt the day he killed 168 people in the 1995 bombing of a federal building in Oklahoma City.

On Snapchat and his public-facing Instagram page, Sauke posted photos of himself holding guns alongside anti-leftist sentiments and expressions of a desire to kill someone, namely a police officer or politician. One post shows him burning an American flag with a blue stripe — a symbol of the pro-law enforcement Blue Lives Matter movement — alongside the caption: "Police lives don't matter."

"We're all from the same cloth," he wrote in another post. "Don't be showing out for any politicians we gotta murder every single one of them."

Federal agents began monitoring Sauke last year after a confidential informant said he posted on social media about manufacturing and selling guns. Several posts on Snapchat showed a gun with black tape around the handle. "Went and got me a sawn-off illegal ASL," he wrote.

"Doesn't matter if you're a felon or not," he wrote in another post, "you should be conceal carrying everywhere you go in 2021. I can help you with that."

Sauke has previously been convicted of illegally carrying firearms and on a drug charge. In January, police obtained forms from his probation officer in which Sauke expressed a "real urge to kill," saying it was a "Christmas miracle" that he had not "put anyone in the dirt yet," according to the charges.

"Cops can feel my wrath too," Sauke wrote. "I've been tazed, stabbed and numbed numerous times that [expletive] doesn't phase me. Its not a matter of if it's a matter of when."

On Jan. 12, as plans circulated for armed rallies at the Minnesota Capitol to protest the election, Sauke began to post more about killing law enforcement there, appearing to urge others to do the same. "If its only me out here killing police," he posted, then the "left" will cast him as a white supremacist.

On Jan. 15, he met the ATF agents in a parking lot in Fari­bault, both posing as potential customers interested in buying guns. He sold one of the agents a gun for $1,500 and they paid him another $900 after negotiating another sale, according to the charges.

Sauke told the agents he sold 120 firearms last year, according to the charges, and he showed them pictures of other guns on his cellphone.

After arresting him, the agents saw the sawed-off shotgun in his car next to some ammunition, charges say.

Andy Mannix • 612-673-4036