A Cincinnati man is under arrest after he allegedly plotted to bomb the Capitol in support of ISIS, the FBI said Wednesday.

Christopher Lee Cornell, 20, was reportedly arrested after buying two semi-automatic rifles and 600 rounds of ammunition in an undercover FBI sting.

The FBI reportedly began investigating Cornell after he began professing support for ISISTand threatening members of Congress online. Via the Boston Herald:

The FBI was alerted about Cornell in the fall by a confidential informant who told officials the suspect had posted several pro-ISIS statements and videos on social media sites. According to the FBI, Cornell connected with the informant to "make our own group in alliance with the Islamic State here and plan operatives ourselves."

The two allegedly met a number of times to devise a plan to build and detonate pipe bombs at and around the U.S. Capitol, and then shoot employees and officials at the building. According to the criminal complaint, Cornell said he was following the directives of violent jihadists abroad.

He was reportedly charged with attempting to kill a U.S. government officer and possession of a firearm in furtherance of an attempted crime of violence.

[image via AP]