COLUMBUS, Ohio — A man whom the police say they killed hours after he tried to breach the F.B.I.’s Cincinnati office had been on the radar of the federal authorities for months, two law enforcement officials said on Friday.
The officials said federal investigators had been looking into whether the man, Ricky Shiffer, 42, of Columbus, had been involved in the Jan. 6 attack on the U.S. Capitol. They also said the F.B.I. had received a tip about Mr. Shiffer in May that was unrelated to Jan. 6, and agents opened a separate inquiry that included conducting interviews in Florida and Ohio.
A neighbor at an apartment complex in Columbus where Mr. Shiffer lived, who declined to give his name, said federal agents had visited the property a few weeks ago and had asked him questions about Mr. Shiffer, including what time he left home most days and when he returned.
Law enforcement officials separately said they were investigating whether Mr. Shiffer appeared in a video posted on Facebook on Jan. 5, 2021, showing him attending a pro-Trump rally at Black Lives Matter Plaza in Washington the night before the Capitol was stormed.
The authorities said Mr. Shiffer, who was wearing body armor, tried to breach the entrance to the visitor screening facility of the bureau’s Cincinnati office on Thursday morning, but fled after an alarm was set off and agents responded. He was later spotted by a state trooper on a nearby interstate and chased into a rural area, where officers fatally shot him that afternoon after a lengthy standoff.
State and federal officials said little publicly on Friday about the circumstances of the attack at the F.B.I. office or Mr. Shiffer’s motivations, even as online posts suggested he was a supporter of former President Donald J. Trump who had reacted with outrage when federal agents searched Mr. Trump’s Florida home earlier this week.
A day after that search, someone with an account bearing Mr. Shiffer’s name posted messages on Mr. Trump’s social media platform, Truth Social, recommending that “patriots” go to Florida and kill federal agents. On Thursday, the same account also appeared to confess to an attack on the F.B.I.
In a series of recent posts, the account had railed against law enforcement and issued a “call to arms,” saying that for two years, “They have been conditioning us to accept tyranny.” When someone asked whether he was proposing terrorism, the account responded: “I am proposing war.”
The New York Times could not immediately confirm whether the Truth Social account, or other social media accounts, belonged to Mr. Shiffer.
The attack in Ohio came during a week when many Republicans had criticized the F.B.I. for the search of Mr. Trump’s home, with some calling it a dangerous weaponization of the Justice Department. Some figures on the right also issued broader calls for violence and civil war.
On Thursday evening, Christopher A. Wray, the F.B.I. director, defended the bureau and decried attacks on law enforcement.