"The time had come that we needed to arrest them and take them down," McQuade told The Associated Press in an interview at her office.
Across the street in Detroit federal court, Stone was arraigned Tuesday and was ordered held without bond until a hearing Wednesday.
McQuade said the "most troubling" finding of the investigation was that Hutaree members plotted to make a false 911 call, kill responding officers and then use a bomb to kill many more at the funeral.
The nine suspects face seditious conspiracy charges after weekend raids in Michigan, Ohio and Indiana. Eight appeared in court Monday.
It was not immediately clear whether any of the suspects had lawyers.
FBI agents moved quickly against Hutaree because its members were planning an attack sometime in April, McQuade said. Members had been undergoing paramilitary training, including learning how to shoot guns and make bombs, since 2008, according to an indictment. Authorities seized guns in the raids but would not say whether they found explosives.
A handful of the group's members were arrested without incident during a Hutaree meeting Saturday night in Ann Arbor, Mich., McQuade said. She said authorities chose that time and place because they knew it would lessen the chance that other people would be around.
Hutaree says on its Web site its name means "Christian warrior." The group quotes several Bible passages and declares: "We believe that one day, as prophecy says, there will be an Anti-Christ. ... Jesus wanted us to be ready to defend ourselves using the sword and stay alive using equipment."
The Web site does not list specific grievances against law enforcement and the government.
The site features a picture of 17 men in camouflage, all holding large guns, and includes videos of armed men running through the woods. Each wears a shoulder patch that bears a cross and two red spears.
