S13, E1: Louise and Hugh Murdoch, both well-respected professors at Stuyvesant College, are found shot to death in their apartment. The murder weapon, a Beretta 9 mm, is recovered in a nearby trashcan. Detectives Briscoe (Jerry Orbach) and Green (Jesse L. Martin) begin their investigation at the unfortunate couple's offices. Hugh Murdoch was a biomedical researcher who was involved in a controversial type of stem cell research. Initially they think some pro-life groups might have been behind it, but they realize that's not the case.