A sixth man, Barry Croft, 44, of Bear, Delaware, is being transferred to Michigan to face the conspiracy charge.
Defense lawyers on Friday argued there was no conspiracy and that the accused were merely exercising their First Amendment rights to free speech and assembly and that threats to kidnap and kill Whitmer were "loose talk."
One video released Friday shows Caserta and other accused plotters emerging from a vehicle and firing weapons during assault training.
"Training for things like breaching a house, using improvised explosive devices, assaulting cars, exfiltration from cars, this is a lot of nonstandard stuff that raised some flags," Assistant U.S. Attorney Nils Kessler said in court Friday.
The trove of evidence includes text messages exchanged among members via an encrypted app in a group chat titled "F - Around and Find Out."
In one text, Garbin used symbols and emoticons to suggest blowing up a bridge near Whitmer's vacation home would slow law enforcement responding to the kidnapping, prosecutors said.
The texts include one from Harris discussing the kidnapping plot, prosecutors said.
"Have one person go to her house," Harris wrote. "Knock on the door and when she answers it just cap her."
Daniel Harris sent this text during the kidnapping plot, suggesting someone go to Gov. Gretchen Whitmer's house and "just cap her," prosecutors said.
Fox appears in another video released by the government.
In the short clip, Fox is shown rapidly reloading one weapon and brandishing a firearm from a holster on his right hip.
The state and federal cases filed last week have focused attention on anti-government extremism in Michigan amid fallout from lockdown orders aimed at stemming the spread of COVID-19.
Members of the alleged conspiracy voiced displeasure with the lockdown, some protested at the Capitol and discussed "taking out" another state leader, Virginia Gov. Ralph Northam.
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