Not confirmed. I think it was Quinn.
Here’s the logic.
Quinn need’s cash she knows the DIKs have money in the safe. But she needs a distraction. Here’s the theory;
Camilla is banging Rusty - Mona is alone she thinks Cammy is probably banging some guy. John-Boy here’s moaning out side Rusty’s room. He thinks someone is fucking in there.
Riona is outside the Library - She is feeling guilty about something. I think she is the one who grabs the laptop and posts the cluck whilst Rusty is balls deep.
The painting over the ‘fabled‘ DiK safe is partially removed. When MC asks Rusty he says it shouldn’t be like that and he’ll sort it out.
So Cammy bangs Rusty, while he has a face full of dat booty, Riona takes the laptop and gets ready to post the Cluck. Meanwhile Quinn follows Tommy out of the main party towards his, Jamie and Rusty’s room. Cluck get’s posted, Rusty run’s from his room searching for the missing laptop, Quinn sneaks into his room hoping to get into the safe.
It’s possible Tommy has some involvement, he previously had a conversation about taking responsibility for some HoT activity Quinn had planned. I’m not sure if exactly what was ever revealed.