Mr. Cobb is found dead in his room. It has no window and the door was locked. His wife calls the only four people who had the key into questioning.
- Sophia, the maid: “I came to wake up Mr. Cobb at 7 a.m. and when I saw him, I screamed!”
- John, the butler: “When I heard Sophia scream, I immediately ran to the room turned on the light and saw that Mr. Cobb had a knife in his neck.”
- Sarah, the governess: “I rushed up along John and when he turned on the light there was blood everywhere, no wonder Sophia screamed.”
- Jack, the cook: “I was prepping breakfast from 6 a.m. to 8 a.m. I didn’t see anything.”
Question: Who is the killer?
Sophia, the maid. If the room has no window and John had to turn on the light, she could not have seen the dead body unless she already knew he was there.