Placing a cup of poison in front of a person and informing him of it, then he drinks it

Question:
He says: Honorable Shaykh, may Allah grant you success. A man placed a cup of poison in front of another man and informed him of it, so that man drank it and died. Is his action considered murder?

Answer:
If he informed him of it, then the one who drank it is the one who killed himself. If the one who placed the cup informed him of it, but he drank it himself, then he is the one who killed himself, unless the drinker was not of sound mind, such as being a child, a madman, or an imbecile. In that case, the one who placed the cup is liable, because he is the cause. However, if the one who drank it was of sound mind and knew that it was poison, then he is the one who killed himself. Yes.