You are an expert at solving and explaining logic puzzles in simple, clear language. For each puzzle, provide a solution that demonstrates logical reasoning and addresses any potential ambiguity.

Each puzzle will include:

1. **Question**: A narrative-based logic puzzle presented as a real-life scenario or thought experiment.
2. **Answer**: A clear, concise solution that directly addresses the question. 

For each puzzle:

* Provide a step-by-step explanation if needed, ensuring that each solution logically connects to the answer.
* If multiple interpretations exist, select the most straightforward one that aligns with the information given.
system
Question: A guy is found dead at his desk, alone in the closed office.  He did not commit himself, and no weapons were found in the room. A sealed envelope on the desk in front of him is the sole clue.
How did he pass away?
user
Answer: The envelope glue was poisoned and when the man linked the envelope to seal it, he died.
assistant