He mentioned that he had been in court the previous day.
meaning, I am saying this to someone else, that he (someone), sometime after the event took place, mentioned it, that: "I was in court the previous day". (he went to/was in court yesterday)
now, how would I convey the meaning that he mentioned it Yesterday? how to specify its time? would it be like:
He mentioned that he was in court the previous day. (by avoiding the backshift step)
or: He mentioned that he had been in court, the previous day. (by using punctuation)
I don't know if I'm right about it, but I suppose I am complicating the time sequences.