Heather Laurie Holden (born December 17, 1972) is an American-Canadian actress and human rights activist. She is perhaps best known for her roles as Marita Covarrubias on The X-Files, Adele Stanton on The Majestic, Cybil Bennett on Silent Hill, Amanda Dumfries on The Mist, Olivia Murray on The Shield, and Andrea on The Walking Dead..