The accused D.C. pipe bomber has been speaking with investigators for hours, admitting he planted the devices and expressing doubts about the outcome of the 2020 presidential election, a source close to the investigation tells Fox News.

The explosive devices were placed near the Republican and Democratic National Committees’ headquarters on Capitol Hill just hours before the Jan. 6, 2021 congressional certification that erupted into riots by demonstrators.

The suspect, Brian Cole Jr., is scheduled to make a federal court appearance later Friday for a first appearance before a magistrate as FBI interviews with him continue. He has not yet entered a plea.

FOX NEWS POLITICS NEWSLETTER: WHO IS BRIAN COLE, THE DC PIPE BOMB SUSPECT? 

Cole was arrested on Thursday outside his Virginia home and has since made multiple statements to federal law enforcement, said the source.

A second source tells Fox News that the suspect’s possible motivation is just one piece of information developed early in an active, ongoing investigation and that no full picture of the suspect has emerged.

But the suspect’s statements about the 2020 election and his apparent support for President Donald Trump may offer a hint at a possible motive for allegedly planting the pipe bombs, which did not detonate.

FBI and DOJ officials have been officially mum on a motive, but indicated more information would be released soon, along with possibly more criminal charges.

NBC first reported that the suspect had expressed doubts about the 2020 election.

WHO IS BRIAN COLE, THE DC PIPE BOMB SUSPECT?

Surveillance footage released by the FBI shows a suspect placing the two explosive devices by the buildings in Washington, D.C.

The explosives found hours later by law enforcement were determined by the FBI to be “viable devices that could have been detonated, resulting in serious injury or death.”

Cole is charged with transporting an explosive device in interstate commerce and with maliciously attempting to destroy property using explosive materials, according to a criminal complaint. 

Attorney General Pam Bondi stated on Friday that she anticipates additional charges will be filed in the case.

FBI Director Kash Patel on Thursday blasted the Biden administration for its handling of the investigation, telling “Fox News @ Night Now” host Trace Gallagher that the prior administration “sat on” evidence for four years and failed to make a breakthrough in the case.

In contrast, he said, the FBI under his leadership incorporated cell phone geolocation data to hunt for the suspect.

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“We went back and looked at the cellphone tower data dumps. We went back and looked at the providers and what information they provided pursuant to search warrants at the time and asked questions such as why weren’t all the phone numbers scrubbed, why aren’t they connected and why wasn’t there any geolocational data done?” Patel said.

“That is either sheer incompetence or complete intentional negligence — and neither of which is acceptable for this FBI.”

Fox News’ Anders Hagstrom, Nora Moriarty and Greg Wehner contributed to this report.