Payback

S4 E11: Natalia's mission to solve cold cases is a success when a man imprisoned for rape is set free six years later. However, when the CSIs reexamine the evidence, find the true culprit and go to arrest him, they find that someone else has already taken justice into their own hands and killed him. Meanwhile, Alexx discovers that a corpse in her morgue may have died due to surgeon error on the operating table.