CBS

Season 2: Episode 21 - 18-5-4

18-5-4: Jane and company investigate the death of an introverted mathematical genius, Noah Valiquette, who was murdered by a gun-wielding clown who then cut off his index finger. When Noah's wife reports a break-in at their home and a safe is discovered, along with the severed finger, the team begins to understand that Noah was working on a top-secret de-coding project that cost him his life.