YOU SAID:

they caught the thief who stole the painting, which was later found

INTO JAPANESE

彼らは後で発見された絵を盗んだ泥棒を捕まえた

BACK INTO ENGLISH

They caught a thief who stole a picture that was later discovered

INTO JAPANESE

彼らは後で発見された写真を盗んだ泥棒を捕まえた

BACK INTO ENGLISH

They caught a thief who stole a picture that was later discovered