There should be an icon when you talk to her if you haven't confronted Blank yet. I'm pretty sure that the police path and vigilante path are mutually exclusive, so if you've already resolved it through the P.I., then you can't convince her to talk to the police.
Viewing post in Love & Sex : Second Base comments
I'd hold off on starting the new playthrough until 20.5 comes out. I tried out the police path on a save I had from when she was telling me about it, and as far as I can tell, it got me to the same point, just in a different way. Blank was out of the picture, and Alexis and you see the news on TV.
If there was another event after that, it's possible that I missed it. I don't recall having seen any pop-up or change in her story tracker, but her KP cap was different.