YOU SAID:

i shall not find who perhaps killed the balloon i was supposed to kill

INTO JAPANESE

私が殺すはずだった気球を誰が殺したのかはわからない

BACK INTO ENGLISH

I don't know who killed the balloon I was supposed to kill

INTO JAPANESE

殺すはずだった気球を誰が殺したのかわからない

BACK INTO ENGLISH

I don't know who killed the balloon that was supposed to kill me

INTO JAPANESE

私を殺すはずだった気球を誰が殺したのかわからない

BACK INTO ENGLISH

I don't know who killed the balloon that was supposed to kill me