YOU SAID:

i'm an under cover cop

INTO JAPANESE

私はアンダーカバーの警官です

BACK INTO ENGLISH

I am a cop at under cover

INTO JAPANESE

私はカバーの下にある警官です

BACK INTO ENGLISH

I am a policeman under the cover

INTO JAPANESE

私はカバーの下に警官です

BACK INTO ENGLISH

I am a policeman under the cover