"We are aware the suspect [Warner] sent materials which espoused his viewpoints to several acquaintances throughout the country," federal investigators said in a statement acquired by ABC-affiliate WKRN.
Anyone who may have received material from Warner is asked to contact the FBI at (800)-CALL-FBI.
The Associated Press reported on Dec. 30 that his girlfriend, Pamela Perry, told police that he was building bombs in an RV trailer at his residence back on Aug. 21, 2019.
Police then went to Warner's home, located about 1.5 miles (2.4 kilometers) from Perry's home, but he didn't answer the door when they knocked several times. They saw the RV in the backyard, the report said, but the yard was fenced off and officers couldn't see inside the vehicle.
The report said there also were "several security cameras and wires attached to an alarm sign on the front door" of the home. Officers then notified supervisors and detectives.
"They saw no evidence of a crime and had no authority to enter his home or fenced property," the police statement said.
After officers visited Warner's home last August, the police department's hazardous devices unit was given a copy of the police report. During the week of August 26, 2019, they contacted Throckmorton. Police said officers recalled Throckmorton saying Warner "did not care for the police," and that he wouldn't allow Warner "to permit a visual inspection of the RV."
The Associated Press contributed to this post.