Disarmed and Dangerous - S9-E12
Plot hole: Series 9 episode 12: "Agent Hartford" had no fingerprints: the FBI "removed" them. But when they find the street piece that Vinny had, they dust it and say that Hartford's prints were all over it. This might be OK, if he were a real agent on the books (but they never heard of him at Quantico), or if he were a real criminal - but in that case, they would have sussed it all out earlier.
Answer: The episode on CSI:NY was called "Love Runs Cold" and first aired on October 4, 2006 (Season 3, Episode 3) and involves the investigation of a model found stabbed to death by an ice dagger.
OneHappyHusky