Revealing mistake: When Warrick takes out the contents of the wallet, he removes a few 100 dollar bills. If you look carefully, you can see on the top bill it says "For Motion Picture Use Only."
Revealing mistake: Season 5 Episode 18 "Spark of Life": when they show a closeup of the badly-burned woman during her debridement, it can be seen that even though her eyebrows and hair and, in fact, 90% of her skin has been burned away, she still has long, full eyelashes.
Revealing mistake: Season 5 Episode 4X4. When Warrick and the young coroner are examining the dead woman in the RV, look closely as you can see her blink.
Revealing mistake: Willows discloses a laptop with the city's grid layout inside the welder's truck, and grabs her cell to call Grissom. Just as she presses last number, he immediately answers, without so much even a ring.
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