Question

Which element is used as a rat poison and is found in the title of the murder mystery?

Answer 1

The element that is used as a rat poison and found of the murder mystery is Arsenic.
Hope this helped you!

Answer 2

Arsenic.

Arsenic is a chemical element with the symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid.