The Walter E. Washington Convention Center in Washington, D.C., on April 29, 2020. (Saul Loeb / AFP / Getty Images) BlackCat ransomware group leaks files stolen from D.C. convention bureau The BlackCat ransomware group, also known as ALPHV, posted a trove of data stolen from Events D.C., Washington, D.C.'s convention bureau. Dec 19, 2022 By Benjamin Freed