WASHINGTON (AP) — A federal appeals court on Friday upheld the conviction of a former U.S. Capitol police officer who tried to help a Virginia fisherman avoid criminal charges for joining a mob's attack on the building that his law-enforcement colleagues defended on Jan. 6, 2021.

A three-judge panel of the U.S. Court of Appeals for the District of Columbia ruled that the government's evidence against Michael Angelo Riley "readily supports" his conviction on an obstruction charge.

Riley, a 25-year police veteran, argued that prosecutors failed to prove a grand jury proceeding was foreseeable or that he deleted his Facebook messages to affect one. The panel rejected those arguments as "flawed."

"Riley was a veteran Capitol Police officer concededly aware of the role of grand juries in the criminal process, and his own messages showed he expected felony prosecutions of unauthorized entrants into the Capitol building on January 6," Judge Cornelia Pillard wrote.

In October 2022, a jury convicted Riley of one count of obstruction of an official proceeding but deadlocked on a second obstruction charge. In April 2023, U.S. District Judge Amy Berman Jackson sentenced Riley to two years of probation and four months of home detention.

Riley, a Maryland resident, was on duty when a mob attacked the Capitol on Jan. 6. That day, Riley investigated a report of an explosive device at Republican National Committee headquarters and helped an injured officer.

The following day, Riley read a Facebook post by Jacob Hiles, a fisherman he knew from YouTube videos. Hiles wrote about his own participation in the riot and posted a video of rioters clashing with police.

Riley privately messaged Hiles and identified himself as a Capitol police officer who agreed with his "political stance."

"Take down the part about being in the building they are currently investigating and everyone who was in the building is going to be charged. Just looking out!" Riley wrote.

Riley deleted their private messages after Hiles told him that the FBI was "very curious" about their communications, according to prosecutors.

Hiles pleaded guilty in September 2021 to a misdemeanor charge related to the Capitol riot and was later sentenced to two years of probation.