Taken from the manga 暗殺教室.
暗殺【あんさつ】は勉強【べんきょう】の妨【さまた】げにならない時【とき】にと言【い】ったはずです
My best guess for this sentence would be:
I'm sure there has been a time I've told you that assassinations shouldn't get in the way of your studies
I'm mostly relating 時に here to 'has been a time' here, but what throws me off is the と after it so would it be included in what he had said before? And the translation just feels a bit weird in general. I'm mostly trying to think of the difference between this sentence and 暗殺は勉強の妨げにならないと言ったはずです with the 時に.
I'm sure i've told you that assassinations shouldn't get in the way of your studies
Is that right?