At Conlan's office, the man himself is like, I don't know anything, so go find out who killed my wife. The ADAs suggest that somebody in Conlan's office figured out what he was doing -- eavesdropped on his calls, read his emails, somehow guessed that he's responsible for the blackouts. Conlan continues to claim that it "just happened," but as he's escorting them out, they run into Katie. Katie and Conlan leave, but not before Katie asks for the detectives' contact info, so she can thank them. Aw. Rubirosa says she'll get the addresses for Katie. Then Cutter spots a big aquarium with a sticker on it. The sticker is covering another sticker, and the second sticker is from...the Costas's pet store. A woman at a nearby desk says that the guy who installed the tank is named "Rick, Nick, something," and that the guy who sits near the aquarium is an "IT geek" who just happens to have called in sick for the last few days.
Cut to the interrogation room, where IT Geek Marty is lying, badly, to Green about buying a scorpion fish from Nick. But Marty hacked into Conlan's emails, and Marty and his lawyer chalk that up to simple nosiness, so Lupo tries the diss strategy, theorizing that Marty didn't call any of the shots and that Nick pushed him around. Marty gets sulky, so it's obviously working, until the lawyer calls them on it, and outside, Van Buren says that Marty erased the relevant emails, so they have no evidence to tie him to Conlan unless Conlan himself testifies.
Conlan, who is packing to leave town, isn't going to have anything to do with that. The ADAs pressure him, saying they don't have a warrant on Barkin, so if Conlan can't testify to the link with Marty, he might walk. Or something. It doesn't matter because Conlan is still balking; he'll go to jail, leaving Katie alone, and if it's not the state that sends him to the clink, the Feds or the SEC will get him. This is why the FBI exchange earlier didn't work; he wouldn't want that agency involved if he thought they'd nail him for the collusion as a result. I know he was desperate to find his daughter but it doesn't really line up. Cutter tries to guilt Conlan; no joy.