The chief operating officer of Atlanta’s High Museum of Art has resigned after an internal investigation found that approximately $600,000 was allegedly misappropriated over several years and the matter was referred to federal prosecutors, according to the Atlanta Journal-Constitution.

Brady Lum, who had served as COO since 2019, tendered his resignation on Dec. 9 amid the probe. On Tuesday, the board of the Woodruff Arts Center, which oversees the High, voted to refer the matter to the U.S. Attorney’s Office for the Northern District of Georgia for possible criminal prosecution, the newspaper reported.