ATLANTA — Federal agents arrested four suspected members of a Georgia militia on charges of plotting attacks with toxins and explosives in Atlanta and against unnamed government officials.

The four, who authorities arrested Tuesday, were expected to appear in federal court in Gainesville, Ga., this afternoon.

They were part of a group that also tried to obtain an unregistered explosive device and sought out the complex formula to produce ricin, a biological toxin that can be lethal in small doses, according to a federal complaint.

One suspect discussed ways of dispersing ricin from an airplane in the sky over Washington, court records state. Another suspected member of the group intended to use the plot of an online novel as a model for plans to attack U.S. federal law officers and others, authorities said.

Court documents state that 73-year-old Frederick Thomas told others he intended to model their actions on the online novel “Absolved,” which involves small groups of citizens attacking U.S. officials.

The four men live in the north Georgia towns of Cleveland and Toccoa.