The suspect, Dennis Marx, was shot and killed at the scene, said Forsyth County Sheriff Duane Piper. Marx had driven up to the courthouse and threw out smoke devices and homemade spike strips to prevent officers from reaching him. Both homemade and commercially made explosives were in his car, suggesting he had planned the assault for days, Piper said.
Marx also had water and other supplies, including zip ties that can be used to bind people's hands. Piper said the wounded deputy prevented others from getting hurt when he encountered Marx, though it was not clear if that deputy killed the suspect.
"When the deputy engaged him outside, it saved lives," Piper said. "The entire situation was solved by that deputy's actions."
The deputy, who has been with the department for 25 years, was shot below his knee and is expected to recover. His name was not released.
Few details about Marx were known, though Piper said he had been known to authorities for some time.
The courthouse and nearby businesses were evacuated as the FBI, the Bureau of Alcohol, Tobacco, Firearms and Explosives, and the Georgia Bureau of Investigation investigated.