A Columbia, Missouri man pleaded guilty in federal court to his role in preparing to launch a terrorist attack with persons he believed were members of ISIS but were undercover law enforcement employees, the Department of Justice announced Tuesday.Robert Lorenzo Hester Jr., 28, pleaded guilty before U.S. District Judge Greg Kays on Monday to attempting to provide material support to a designated foreign terrorist organization.Hester, who has been in federal custody since his arrest in February 2017, is a U.S. citizen. He was enlisted in the U.S. Army for less than a year, receiving a general discharge from service in mid-2013.By pleading guilty, Hester admitted that from October 2016 to February 17, 2017, he attempted to provide material support to ISIS, knowing it was a designated foreign terrorist organization that engages in terrorist activity.According to the plea agreement, multiple confidential sources reported to the FBI that Hester had posted a variety of material on multiple social media accounts. Court documents said Hester indicated that he had converted to Islam, expressed animus toward the United States and posted photos of weapons and the ISIS flag, among other material, suggesting an adherence to radical Islamic ideology and a propensity for violence. FBI employees using undercover identities communicated with Hester via social media, texting and personal meetings on several occasions. In those conversations, Hester said that the U.S. government should be “overthrown,” and he suggested “hitting” the government “hard,” while noting that it would not be “a one man job.” Law enforcement officials said Hester identified categories of potential targets for attack, including “oil production,” “military bases,” “federal places,” “government officials,” and “Wall Street.” The Justice Department said Hester specified that “any government building in DC would get attention of everyone.” Hester said he wanted a “global jihad.” Citing his brief enlistment in the U.S. Army, Hester also claimed proficiency with “assault weapons” and said that his favorite firearm was the AK-47 rifle. According to court documents, Hester spoke about the perceived ease with which one could gain access to a military base.Court documents revealed Hester established an apparent willingness to act on the statements that he made online. The Justice Department said an undercover FBI employee conversing online with Hester offered an in-person meeting with a like-minded “brother.” The Justice Department said Hester agreed to meet and subsequently did meet on numerous occasions with a person who was described as, and Hester believed was, a terrorist operative. This person was an employee of the FBI working in an undercover capacity.In the meetings, the Justice Department said the FBI undercover agent made clear to Hester that the undercover was representing ISIS and that the undercover agent was planning an attack that would involve multiple operatives, deploy bombs and guns and result in mass casualties. When he was first arrested, the Justice Department said the FBI employee told Hester that the attacks were planned for Presidents Day in Kansas City.Hester indicated through his statements and actions that he was ready and willing to participate and assist in the “plot.”The Justice Department said Hester obtained items that he was told would be used as bomb components, including boxes of roofing nails. In addition, the Justice Department said Hester did not hesitate when the undercover agent showed him a cache of three machine guns and two handguns that would be used in the “attack,” and two pipes that would be used to construct the “bombs.” The Justice Department said Hester provided information on storage units that could be used to hold the weapons and agreed to obtain additional supplies for the operation.Under the terms of the plea agreement, the government anticipates recommending a sentence of 20 years in federal prison.