I can already say I can't. I mean, obviously from the episode Infiltrator, it's been practically obvious ever since then, but she didn't seem too happy about it when she let Cheshire escape. I honestly think she's either being blackmailed or is being forced to do something and I wonder what it is. It was already revealed that she's most likely not really Green Arrow's niece. Recently, I was watching Bereft, and noticed the way she acted towards Wally when she forgot her memory of joining the team as well. What also got me was what she said about her dad— "Dad! he must've done this, another one of his stupid tests," and when Wally asked her "What tests?" she bluntly replied that she's probably suppose to kill him...meaning she's probably done something like that before or encountered a situation like that...it all leads to a bad past or something more.
Edit: I don't think she's the mole anymore people, lol. I think the creators are making it way too easy for us to imply that she's the mole...which is what they want to do so they can trick us. But continue to leave your opinions.