YOU SAID:

Who ever wrote this was either really tired

INTO JAPANESE

誰がこれを書いたか、本当に疲れていた

BACK INTO ENGLISH

who wrote this was really tired

INTO JAPANESE

これを書いた人は本当に疲れていた

BACK INTO ENGLISH

The person who wrote this was really tired.

INTO JAPANESE

これを書いた人は本当に疲れていました。

BACK INTO ENGLISH

The person who wrote this was really tired.