The bank Mr. Varnell was said to target — the downtown branch of BancFirst, Oklahoma’s largest state-chartered bank — is about a half-mile from the site of that attack.
During a meeting in June with an undercover F.B.I. agent posing as someone who could help him, Mr. Varnell said that he wanted to start the next revolution and that he identified with what is known as ideology, according to an affidavit filed in support of the federal criminal complaint against him. Mr. Varnell sought to form and arm a small militia group, inspired in part by the movie “,” the authorities said.
“I’m out for blood,” Mr. Varnell wrote in one text message to a confidential informant who cooperated with the authorities, according to the affidavit, which was written by an F.B.I. special agent. “When militias start getting formed I’m going after government officials when I have a team,” he wrote. The complaint did not name the informant.
In another text message, Mr. Varnell wrote: “I think I’m going to go with what the okc bomber used. Diesel and anhydrous ammonia.” He was referring to , who for the Oklahoma City bombing. Mr. McVeigh and a co-conspirator, Terry L. Nichols, built a giant fertilizer bomb using ammonium nitrate and racing fuel as their primary ingredients. Mr. Varnell later told the informant to get him ammonium nitrate, adding, “That’s all I need,” according to court documents.
Federal law enforcement officials said the public was not in danger at any time.
“There was never a concern that our community’s safety or security was at risk during this investigation,” Kathryn Peterson, the special agent in charge of the F.B.I. in Oklahoma, said in a statement. “I can assure the public, without hesitation, that we had Varnell’s actions monitored every step of the way.”
The bombing case appeared to have started in December, when the confidential informant told the F.B.I. that Mr. Varnell wanted to bomb the Washington building that houses the offices of the Federal Reserve’s Board of Governors. Mr. Varnell appeared to be especially angry with the banking and financial data system, and expressed interest in attacking corporate data centers and facilities known as server farms, including those run by Facebook and Bank of America, the authorities said.
He told both the informant and the undercover F.B.I. agent that he did not want to kill “a bunch of people.” But when the undercover agent told him in June that any bombing might kill one or more people, Mr. Varnell responded, “You got to break a couple of eggs to make an omelet,” according to the affidavit.
Mr. Varnell also wrote a statement that he wanted posted on Facebook after the bombing, and sent it to the informant, the authorities said. The statement refers to the bombing as an act of “retaliation” for government actions that he said restricted Americans’ freedom.
“It was a wake-up call to both the government and the people,” Mr. Varnell’s statement said, according to officials. “An act done to show the government what the people thinks of its actions.”
A variety of militia groups around the country regard themselves as 3 percenters. The term comes from their belief, debunked by historians, that only 3 percent of American colonists fought in the Revolution. These groups have been accused of promoting racist and apocalyptic views, but they deny being racist or anti-government, describing themselves instead as pro-Constitution, pro-gun and, in many cases, pro-President Trump.
Mr. Varnell lives in Sayre, Okla., with his mother and other relatives. The authorities said that he had been outfitting a bunker next to his home with end-of-the-world supplies and that he had spoken to the informant of using marijuana and methamphetamine. He was arrested in 2013 in Weatherford, Okla., and charged with domestic assault and battery by strangulation; it was not immediately clear how that case was resolved.