Elementary - Season 4 – Bonus Inside

In Episode 11 ("Down Where the Dead Delight") , a bomb detonates in a morgue, forcing Holmes and Watson to solve a murder without any physical "pieces" of evidence.

While the artwork in Episode 20 is the most direct literal match, "piece" could also refer to: Elementary - Season 4

The artwork serves as the bridge between a current homicide and an unsolved mystery from the past. Other Notable "Pieces" in Season 4 In Episode 11 ("Down Where the Dead Delight")