Wunmi Mosaku, star of Jack Thorne's C4 drama Kiri, has joined the cast of BBC crime drama Luther as it returns for a fifth series. Mosaku, who has also appeared in Sky Atlantic/Showtime's Guerrilla and Netflix's Black Mirror, will play D.S. Catherine Halliday in the BBC Studios-produced series. Mosaku, who is represented by Scott Marshall, Gersh and Principal Entertainment LA, joins Idris Elba, Dermot Crowley, Michael Smiley and Patrick Malahide in the four-part drama…