The admission came in an aside to a federal memorandum urging that Buford “Bucky” Rogers be sentenced to five years and three months in prison. Rogers, 25, is scheduled to be sentenced Monday in U.S. District Court in Minneapolis.

Rogers pleaded guilty in January to illegal possession of a semi-automatic rifle, prohibited because he is a convicted burglar, and possession of two black powder-and-nail explosive devices.

Federal prosecutors say Rogers’ arrest last May was necessary after the FBI was tipped off that he had a large cache of weapons and planned to attack the Montevideo police station, National Guard armory and a local radio tower, but he was never indicted on terrorism charges. Prosecutors say he should get five years because of “numerous” previous arrests, including third-degree burglary and possession of illegal weapons, suggesting he has “exhibited consistently dangerous criminal behavior over the course of many years.”

Federal Public Defender Andrew Mohring urged this week that Rogers get a two-year sentence, noting in a memorandum that “the facts of this case as it now exists stand in sharp contrast to those broadcast to the press and public when the case opened last spring.”

At the time of his arrest, Mohring said, Rogers was labeled by authorities as a “domestic terrorist.”

“Coming less than three weeks after the Boston Marathon bombings, these accusations were made in an unusually public manner, through news releases and televised interviews,” Mohring wrote.

In the end, Mohring said, the only suggestion that Rogers was planning a violent conspiracy came from a single individual “of untested reliability” who did not meet the definition of a reliable informant.

“Not withstanding the foreboding name” — the Black Snake Militia that authorities claimed Rogers headed — the FBI later acknowledged the group contained only three or four people, Mohring wrote.

“After one and one half years, no additional evidence has been identified to confirm the existence of any plot to attack anyone or any thing,” Mohring wrote.

Federal prosecutors Andrew Winter and Charles Kovats Jr. say Rogers’ arrest was proper, despite a decision not to charge him with terrorism,

At the time of the arrest, they wrote, “the FBI had been informed that the defendant was part of a group cheering the Boston bombing, possessed explosive devices and planned to conduct violent acts imminently.

“The fact that a broader plot was not discovered is not exculpatory,” they added. “It merely evidences the absence of additional inculpatory (incriminating) behavior.”

Prosecutors note that when they searched Rogers’ father’s premises they “uncovered a sizable collection of explosive devices, firearms, ammunition, military clothing and other militia related items. … Beyond the inherently dangerous nature of the devices was defendant’s disregard for the safety of his neighbors in storing the devices in a residential area.”

Mohring argues that Rogers’ past crimes were overstated, and while he admits to possessing dangerous weapons, he did not use them and he has already spent a year in jail.

The FBI’s source for believing there was a terrorist plot, according to court documents released earlier, was a single unnamed witness who first met Rogers at an Arizona “pow wow” in 2012, then moved to Montevideo and stayed with Rogers’ family. The witness told the FBI that Rogers “talked regularly about his plans to use his ‘Black Snake Militia’ to cut off connections to the city of Montevideo, to ‘take out’ a radio tower, to block communication to the city, to raid the National Guard armory and to attack the police station.”

The witness told the FBI around May 1, 2013, that Rogers had cheered the Boston Marathon bombing and planned to attack Montevideo that weekend. It prompted the FBI to assemble about 50 officers and two armored carriers to raid Rogers’ father’s home. Rogers was arrested without incident.

As part of the plea agreement in January, the U.S. attorney’s office agreed to drop two other counts against Rogers, one for possession of two Molotov cocktails, the other for possession of a pipe bomb.