Interview transcripts, crime scene photos, the full report from the post-mortem – it’s all here. The PM concludes cause of death was exsanguination from the knife wound on his neck. The blood spatter in the van tallies. The interview with the cameraman talks about the argument – even Finn’s own PhD student Ian Calloway agrees that the relationship between the two of them was strained. Finn’s hard drive contains a paper written by Sharp, taking full credit for the radar they were testing that night. And Finn himself was a mess. Not looking after himself, drinking more than should be humanly possible. Even experimenting with LSD, although there was none in his blood that day.

But despite all this, Robin still can’t believe that Finn would resort to murder. Even if they had argued, even if he was drunk – to take a knife and slit someone’s throat? It’s ridiculous.

He looks at the photos of the crime scene again. He remembers it from that day, and from the subsequent visit with Craig. Blood everywhere. Mess and papers strewn around. A few plates lying discarded on the side. A window, shut, with a line of blood across it.

He flicks through the reports in front of him and picks up the lab results on the knife. Blood from Simon Sharp, as would have been expected. But the next finding wasn’t so clear. The only fingerprints found on the knife came from Sharp.

He squints at the photos, showing the location of the prints. One on the handle, and a thumbprint on the blade. But nothing from Finn. That doesn’t make sense, surely? As Baker said, it’s contradictory to the arrest. How could Finn have killed him without putting a single print on the knife?

Robin pushes the photos to one side and picks up a memory stick, sent along with the file. He puts it into the side of his laptop and it whirs for a moment, loading.

The memory stick contains three videos, and Robin clicks on the first. It’s footage, professionally filmed, from outside the van. Finn is standing next to Simon Sharp, looking nervous next to the confident Sharp, watching him intently as he talks. Simon’s doing an introduction to the programme, talking about what they’re there to do and the storm they’re expecting that night. He’s clear and charismatic, everything Robin has come to expect from watching the previous episodes of his show. Robin feels a pang of sadness for the man. For the potential he had, before it was wiped out.

Sharp introduces Finn, who then talks for a moment about the equipment they’re testing. Once he’s on a subject he knows, Finn’s manner changes. He looks directly into the camera, his face alive, his voice full of enthusiasm. They cut, and the video ends. The time: 21:46.