@chenando1 It's not only that but Rena's first appearance came a bit after he talked about her to Itsuki, so both of the times he's run into her very clearly tie into times when Itsuki is by far the prime suspect. Given how this time Rena referenced the previous meeting, it's clearly the same girl.
I'll at least give him credit in that after the recent trip of trying to find the fake Itsuki he's probably gotten sick and tired of trying to find out who is who and checking out alibis and marks and all, so if he's of the opinion of, "Bitch if
you want to talk to
me, you've got to make clear which one you are" I can't exactly fault him.