User blog comment:Rassilon of Old/Ep. 124 "Performance" discussion/@comment-167456-20120408135104/@comment-3465526-20120410115325

Red Arrow cannot be the mole -- he is excluded.

As of Infiltrator, RA had been disassociated from the team continuously -- he had no inside knowledge -- he did not join with the team on missions -- following Infiltrator we did not see him again until Targets. There was no establishment of RA having knowlege of Bialya (for example, following the Sportsmaster revelation, he didn't say "he knew about Bialya" which would have established that RA knew about Bialya). Secondarily, RA is the only means by which the Team had access to the Infiltrator tech -- so if he were their "inside source", then he was also the mechanism that so frustrated the Light at the end of Infiltrator (which seems almost as stupid as their having view screens that don't show their faces).

Of course RA COULD be the mole -- so could the Guardians of the Universe -- but there has been ZERO establishment of his moleness. He can be the mole, but only by the writers "cheating".