YOU SAID:
I think my brother killed his best friend so I got a cookie
INTO JAPANESE
兄が親友を殺したと思うので、クッキーを手に入れました
BACK INTO ENGLISH
I think my brother killed my best friend, so I got a cookie
INTO JAPANESE
兄が親友を殺したと思うので、クッキーを手に入れました
BACK INTO ENGLISH
I think my brother killed my best friend, so I got a cookie
That didn't even make that much sense in English.