Unfortunately a bug prevented me from completing the game, or I'm missing something.
[SPOILERS BELOW]
I was at the part where the computer asked me where the liquid came from, and I right-clicked the jar of liquid to propose that is where it came from. It showed the video screen highlight blue, but nothing was said. I then right-clicked multiple video screens and they highlighted blue, but nothing was said. Eventually I could no longer right-click screens to propose responses, they would show a light but no narrative response. I really enjoyed what I played of this game but I'm sad that it seemed to have broke itself right near the end before I was almost done with the investigation.