Marsha Lisa Thomason Sykes is a British television and film actress who is best known for playing Sara Evers in Disney's The Haunted Mansion, Nessa Holt in the first two seasons of the NBC series Las Vegas, Naomi Dorrit on the ABC series Lost, FBI agent Diana Berrigan on the USA Network series White Collar and DS Jenn Townsend in ITV crime series The Bay.