A magistrate judge ruled Thursday that a man who posted on social media about killing a cop ahead of pro-Trump protests last weekend should be kept in custody as his criminal case on illegally possessing a gun moves forward.

Citing the Jan. 6 attack on the U.S. Capitol, a federal prosecutor argued that no conditions of release for 22-year-old Dayton Sauke of Owatonna, Minn., would adequately eliminate the risk Sauke poses to public safety. "The context in which Mr. Sauke made these statements is extremely concerning," said Assistant U.S. Attorney Justin Wesley in a Zoom hearing.

Sauke was charged in Minnesota U.S. District Court this week on one count of illegal possession of a firearm. The criminal complaint states that Sauke sold a homemade gun to two undercover agents of the Bureau of Alcohol, Tobacco, Firearms and Explosives last Friday. After arresting Sauke, the agents found an illegal sawed-off shotgun in his car, and Sauke had told the agents he sold 120 unregistered Glock handguns last year, according to prosecutors.

Court documents contain several images from Sauke's Snapchat account, including one of him smoking a cigarette with the caption: "Extremist violence at the MN capitol this weekend? Even if I kill only 1 cop that's more than antifa cop lovers have ever killed."

He posted photos on Snapchat and his public-facing Instagram account expressing his desire to kill politicians, citing his political stance as "Copkilling" and several images of what he described as a "sawn-off illegal" shotgun.

One Instagram 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." Another shows Sauke carrying a gun along with the caption "Sic Semper Tyrannis," a Latin phrase co-opted by the extremist anti-government Boogaloo Bois movement meaning justice will befall tyrants.

In court Thursday, Sauke's federal defender, Andrew Mohring, emphasized that Sauke has only been charged with possessing an illegal short-barreled shotgun — not threatening police officers or selling firearms.

Mohring said there is "an enormous space between" what Sauke posted and his actions, and that no evidence shows he'd been surveilling law enforcement agents and planning to truly carry out an attack. He said that Sauke is mentally ill and could find better treatment in the community.

Wesley said the criminal investigation into Sauke is still pending — signaling the possibility of more charges — and that Sauke's untreated, undiagnosed mental illness is more reason to believe he could be dangerous.

"To put it into context, he showed up to a sell a gun to an undercover ATF agent with a sawed-off shotgun with ammunition," said Wesley.

Magistrate Judge David Schultz expressed "great concern" over Sauke's release and threat to the public. Schultz requested a psychological evaluation and said the court could revisit the question of release pending trial afterward.

Andy Mannix • 612-673-4036