used to remind someone of a fact, explanation, promise, or refusal you have already stated; used when sth bad has happened, to remind sb that you warned them about it and they did not listen to you
Editorial60% of films
used to remind someone of a fact, explanation, promise, or refusal you have already stated
I told you.
Oxford35% of films
used when sth bad has happened, to remind sb that you warned them about it and they did not listen to you
See, I told you we should have killed that bastard.
Definitions from the Oxford Advanced Learner's Dictionary, 9th edition