Delko, who is working with Assistant State Attorney Rebecca Nevins, is on his way to meet her to go over the CSI evidence theft case that he's been secretly working on. Unbeknownst to him, a suspicious Calleigh follows him after she catches him lying to her. A car bomb goes off and kills Rebecca Nevins. The remote controlled bomb is tracked to the car that was parked next to Nevin's vehicle and it also happens to have come from MDPD impound lot. Relationships sour between the CSI's and Delko as they realize that they are all suspects. Things get even more complicated when evidence of stolen diamonds are mysteriously traced back to Ryan's condo. Ryan is taken into custody. The pieces start to fall together when they realize that Sully, retired CSI, commissioned an old criminal to plant a bomb to scare Nevins. Things went terribly wrong as she wasn't supposed to die. There is a standoff where one of the uniforms behind Horatio shoots Sully. Sully will live but he is a fallen man, much to Horatio's chagrin. Through further investigation and DNA results it is revealed that Ryan had nothing to do with evidence stealing and he indeed has been set up. There is a dirty cop within CSI. Proven through the same DNA test where traces of bacteria can be linked to specific individual we discover that our evidence thief is none other than IAB Sergeant Rick Stetler who was spearheading the entire investigation.