YOU SAID:
なにゆえ人を殺めたか
INTO JAPANESE
なにゆえ人を殺めたか
BACK INTO ENGLISH
Why did you kill a person?
INTO JAPANESE
なぜ殺した?
BACK INTO ENGLISH
Why did you kill her?
INTO JAPANESE
なぜ殺した?
BACK INTO ENGLISH
Why did you kill her?
That didn't even make that much sense in English.