CNN  — 

An armed man suspected of trying to breach the FBI’s Cincinnati field office Thursday was killed in Ohio after a vehicle chase and hours-long standoff with law enforcement, authorities say.

The suspect was believed to be armed with an AR-15 rifle and a nail gun, a federal law enforcement source told CNN, and was wearing body armor, according to officials in an Ohio county.

He was Ricky W. Shiffer, 42, of Columbus, the state highway patrol said Friday.

Authorities have not announced a motive. But Shiffer had been known to the FBI because he had an unspecified connection to the January 6, 2021, riot at the US Capitol, and because he had associates within a far-right extremist group, two law enforcement sources told CNN Friday.

A social media account bearing Shiffer’s name appears to have referenced an attempt to storm an FBI office that day. It also made a “call to arms” – and called for violence against the agency – after the FBI executed a search warrant Monday at former President Donald Trump’s Florida home. Authorities have not confirmed the account belongs to the suspect.

Here’s what we know about the attempted breach and the suspect:

What happened when the suspect tried to enter the office

At about 9:15 a.m. ET Thursday, an armed man tried to breach the visitor screening facility at the FBI field office, the agency said.

“Upon the activation of an alarm and a response by armed FBI special agents, the subject fled northbound onto Interstate 71,” FBI Cincinnati said in a statement.

Ohio State Highway Patrol troopers responded and found the suspect at an interstate rest stop in a Ford Crown Victoria at around 9:37 a.m., the patrol said.

The troopers tried to initiate a traffic stop on the suspect, but he fled and a vehicle pursuit ensued, highway patrol spokesman Lt. Nathan Dennis said. Shots were fired from the suspect’s car during the chase, he said.

The suspect exited the highway at state Route 73 in Ohio’s Clinton County – roughly a 45-mile drive northeast of downtown Cincinnati – and came to a stop on a road nearby around 9:53 a.m., the highway patrol said.

How the standoff unfolded

After stopping, the man got out and “engaged officers,” the highway patrol said. Gunfire was exchanged between law enforcement and the suspect, who used his vehicle for cover, they said.

The suspect was wearing body armor, according to the Clinton County Emergency Management Agency. A lockdown was in effect within a 1-mile radius of the standoff location, the agency said.

The standoff stretched for several hours as law enforcement tried to negotiate with the suspect, the highway patrol said.

“Once negotiations failed, officers attempted to take the suspect into custody by utilizing less lethal tactics,” the agency said. “At approximately 3:42 p.m., the suspect raised a firearm and shots were fired by law enforcement officers.”

The suspect was