Sean "Diddy" Combs' lawyers will question R&B singer Casandra Ventura, known as Cassie, for the first time in his sex-trafficking trial Cassie is the prosecution's key witness and has testified graphic details of alleged sexual and physical abuse at the hands of Combs

Singer Cassie Ventura also known as Cassie arrives for the screening of Killing Them Softly at the 65th international film festival, in Cannes, southern France, Tuesday, May 22, 2012. (AP Photo/Lionel Cironneau,