The FBI arrested a man Wednesday, suspected of planning to bomb the U.S. Capitol, following an undercover investigation that began in 2014.

Christopher Cornell, 20, of Green Township, Ohio, posted to Twitter as Raheel Mahrus Ubaydah, and “voiced his support for violent jihad,” and for ISIL, the FBI said in a criminal complaint.

An undercover informant made contact with Cornell through Twitter in August 2014.

During their conversations, Cornell said that he wanted to wage violent jihad, and that doing so “would be their way of supporting ISIL.”

“I believe we should meet up and make our own group in alliance with the Islamic State here and plan operations ourselves,” Cornell allegedly said in a message he sent to the informant, according to the FBI.

“We already got a thumbs up from the Brothers over there and Anwar al Awlaki before his martyrdom and many others,” he allegedly said.

Awlaki, an American citizen, was killed in a U.S. drone strike in 2011. U.S. authorities allege that he was an operational leader for al Qaeda in the Arabian Peninsula.

Cornell first met with the informant during a meeting in Cincinnati on Oct. 17-18, 2014. At that meeting, the FBI said he told the informant that he wanted to “move” in December, but did not reveal details of his plot.

During a second meeting on Nov. 10-11, the FBI said he laid out details of his plans to build, plant and detonate pipe bombs at and near the U.S. Capitol building before beginning a shooting spree with the informant during the unfolding chaos. He told the informant that he considered members of Congress “enemies,” according to the FBI.

Cornell was arrested after he purchased two semi-automatic rifles in his native Ohio, according to court documents.

The bureau said he was never a threat to the public.

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