A D.C. resident who sympathized with ISIS bought an automatic weapon that he wanted to use to start a "race war," federal prosecutors say.

Clark Calloway, 38, was arrested by FBI agents Thursday after he arranged to buy an AK-47 from an FBI informant, court documents say.

He faces federal charges of possession of a firearm by a felon and transportation of a firearm with the intent to commit a felony.

"Soon the great killing will commence," Calloway wrote in a Facebook post April 20, prosecutors say.

Calloway, who served in the U.S. Marine Corps, allegedly spoke about attacking police stations. He specifically referenced the First District station on M Street SW.

He was arrested in his apartment building on Webster Street in Northeast D.C., about a mile southwest of the Fort Totten Metro station.

Calloway is a construction worker who lived alone and served time in prison for stabbing someone, a 30-page affidavit says. He pleaded guilty in December 2002. After his release, he was ordered to receive mental health and substance abuse treatment.



The FBI began investigating Calloway in June after an employee saw his public Facebook page showed "pictures associated with jihad and terrorism, including individuals walking with rocket launchers, machine guns and other weapons, and individuals carrying the black flag commonly associated with [ISIS]."

Other posts, published to multiple pages, targeted police officers and white people.

Prosecutors say Calloway denied planning to carry out an attack, and characterized many of his Facebook posts as "propaganda" and examples of "talking trash" to followers.

Calloway appeared in court Friday and was polite and reserved. He is being held in advance of a preliminary hearing next week.