A federal judge denied bail Tuesday for a Minnesota man authorities say was amassing an arsenal of guns to use against police before his arrest, and had idolized the person who killed five people at a gay nightclub in Colorado last month.

Magistrate Judge Elizabeth Cowan Wright ruled that no restrictions were sufficient to ensure that River William Smith, 20, would not pose a danger to public safety as he awaits trial on weapons charges.

Smith did not speak or enter a plea during his detention hearing.

"Law enforcement took him down before he could execute his plan," federal prosecutor Manda Sertich told the court.

Defense attorney Jordan Kushner argued that there was no evidence that Smith actually intended to hurt anyone, or that his "inflammatory" comments about Blacks, Jews and gays in social media exchanges with an FBI informant constituted threats against any specific individuals.

"There's a big difference between threats and thoughts and doing things," Kushner argued.

NEBRASKA MAN ID'D AS MINNESOTA COLD CASE MURDER VICTIM

Smith is charged with possession of a machine gun — specifically devices to convert guns to fully automatic fire — and attempting to possess unregistered hand grenades. He paid a second FBI informant $690 for four "auto sear" devices and three dummy grenades shortly before his arrest last Wednesday, prosecutors allege.

FBI Special Agent Mark Etheridge testified that when Smith was arrested he had a loaded Glock 17 semiautomatic handgun, with three full magazines for a total of 52 rounds of ammunition, including the bullet in the chamber. He was wearing soft body armor designed to stop handgun rounds. A search of his car turned up an "AR-style" rifle and two other handguns, as well as a "drum magazine" for the rifle that held 100 rounds.

Smith lived with his grandparents in the Minneapolis suburb of Savage. Four people who acknowledged they were family members attended the hearing, including his grandmother, Roberta McCue, and a woman the grandmother identified as Smith’s mother, but they all declined to comment on the case. Kushner also declined to comment afterward.

mugshot for River Smith

River William Smith, above, who idolized the man who killed five people at a Colorado gay nightclub and was building an arsenal to use against the police, was arrested last week as he allegedly tried to buy weapons from an informant. (sherburne County Jail via AP))

According to the charging documents and Etheridge's testimony, Smith had expressed interest in joining neo-Nazi paramilitary groups; called the Colorado nightclub killer a "hero;" expressed sympathy for the shooter who killed 17 people at a high school in Parkland, Florida, in 2018; described Black people as "agents of Satan" and expressed hatred of Jews. He said he carried a note cursing police inside his body armor so that police could find it after his death.

LESS THAN 20% OF MINNESOTA RESIDENTS CURRENT ON COVID-19 SHOTS

The agent also went over a 2019 incident — described earlier in charging documents — inside Smith's grandparents house, when he was 17, in which he fired three rounds from an AK-47-style assault rifle. His grandmother suffered a minor hand injury in the process. Under a probation agreement, Smith was barred from using or possessing firearms until he turned 19.

But the documents allege that McCue bought her grandson around 1,000 rounds of ammunition this fall. Minnesota law prohibits people under age 21 from buying handgun ammunition.

Under questioning from Kushner, Etheridge acknowledged that Smith did not resist arrest last week. But Sertich presented a partial transcript of a recent phone call from jail between Smith and his grandmother in which he said: "Maybe I should have. I didn't even have the option to do anything bad."

According to the transcript, Smith described the officers who arrested him to her as "15 guys fully drawn." She told Smith she had never trusted the informant, it said.

Authorities began investigating after getting a call in September from a retired police officer who was working at a gun range that Smith frequented. He told them he was concerned because of how Smith practiced shooting from behind barriers while wearing heavy body armor designed to stop rifle bullets, and conducting rapid reloading drills.

CLICK HERE TO GET THE FOX NEWS APP

On Nov. 11, FBI agents observed his grandmother driving him to another range and waiting in the parking lot. A surveillance photo shows him wearing a "Punisher" face mask, a symbol used by some right-wing extremist groups. On a Nov. 16 visit to the club, he told the informant he was "dedicated to dying in the fight with the police," the documents say.

Prosecutors charged Smith via a complaint, a document they sometimes use when they're in a hurry to arrest someone. The case is now expected to go to a federal grand jury for the formal indictment necessary to bring him to trial.