CSI: New York - Spoilers

Episode 4.21 – Hostage (Season finale airing May 21): A bank robbery goes terribly wrong: someone dies and the robber takes everyone hostage (including a three-month pregnant woman). One of the robber’s demands is that a CSI team proves he didn’t kill the deceased. It is possible the robber appears in another episode next season. Source: SpoilerFix.com