Cold Fusion: Part 2 (S05E12)

The Anti Terrorist squad has the Cold Case HQ under lock-down, and the team are kept quarantined until the substance that knocked out Felix can be identified. Spencer has gone to apprehend the man who left his DNA at the campaigners' murder scene but is shot at and loses contact with Boyd. Boyd realises that his investigation is being thwarted by a very powerful insider. (iTunes)