A criminal complaint filed in U.S. District Court in Ohio charges Christopher Lee Cornell with attempting to kill officers and employees of the United States.

Cornell, also known as Raheel Mahrus Ubaydah, was arrested as he took control of a firearm during an undercover FBI operation in southwestern Ohio, the FBI said. The public was never in danger in the investigation, said John Barrios, acting special agent in charge of the FBI’s Cincinnati division.

A phone message and an email were left Wednesday for attorney Karen Savir, a federal public defender listed in court records as Cornell’s attorney. A working phone number could not be found for Cornell’s family members.

The complaint alleges that an FBI informant began supplying agents with information about Cornell last year. The informant and Cornell, who’s 20 and lives in Green Township, first began communicating through Twitter in August 2014 and then through an instant messaging platform separate from Twitter, according to the complaint.

“I believe we should meet up and make our own group in alliance with the Islamic State here and plan operations ourselves,” Cornell wrote in an instant message, according to the court document.

The two met in person in October in Cincinnati and again in November, the complaint states. Cornell told the informant at the November meeting that he considered the members of Congress as enemies and that he intended to conduct an attack on the Capitol, according to the complaint. The document says Cornell discussed his plan for them to travel to Washington and conduct reconnaissance of the security of government buildings including the Capitol before executing “a plan of attack.”

Cornell planned for the two to detonate pipe bombs at and near the Capitol and then shoot and kill employees and officials, and Cornell had saved money to fund the attack, according to the complaint.

Cornell was arrested after buying two semi-automatic rifles and about 600 rounds of ammunition, authorities said.

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