CSI 第9季(Season 9) 第23集(Episode 23) It's a Tough Job, But Catherine's Gotta Do It (1)

In the first part of the two part season finale, a member of the drug task force is murdered in an explosion which leads the team to a deadly street gang. Sergeant Curtis helps the team to solve the murder and to take down the gang. Also, the lab techs must take polygraph tests because it is suspected that there is a mole inside the lab.