Here is the clause they were prosecuted under:
Whoever maliciously damages or destroys, or attempts to
damage or destroy, by means of fire or an explosive, any building,
vehicle, or other personal or real property in whole or in part owned or
possessed by, or leased to, the United States, or any department or
agency thereof, shall be imprisoned for not less than 5 years and not
more than 20 years, fined under this title, or both.
There was nothing malicious about setting a back fire to protect property in 2006.
The prosecution of them under the anti-terrorist act was malicious.