She tried the previous four videos, which were much shorter, and it turned out that these were all out-takes of the same short segment. In the first one, Alex fell over his words, made a burbling sound, laughed, and went to turn the video off. In the second one, he made it through the intro, and then tripped over trying to move into the plank. He collapsed into a fit of giggles that was infectious and, for Hanson, achingly sad.

The fifth clip was less engaging. Alex was filming himself doing 2k on the Concept 2 rowing machine. He gave a brief introduction, saying he was filming it for posterity, and then he turned some pounding music on and started.

Hanson skipped on twice, seeing nothing much of interest. And then, at five minutes in, Alex suddenly faltered, and came to a stop. He let go of the handle, breathing heavily, and then he let out a roar. He undid his foot straps with a furious rush, and staggered to his feet, swinging close to the camera.

‘For fuck’s sake, you fucking pussy!’

Hanson actually flinched as he shouted. It didn’t seem possible that it was the same voice as those cheerful, encouraging comments on the other videos.

His movements were no less aggressive. He started to kick the wheel of the Concept 2, lending a rhythm to his shouts of, ‘What – the – fuck – is – wrong – with – you?’

The anger went on for a good minute, and then Alex collapsed onto the floor and began to cry, still half raging between the tears. Calling himself a useless twat. A pathetic fag.

Hanson paused it, wondering for a moment where the rage had come from. Then she remembered what Phoebe had told them.

He was a bit of a mummy’s boy. At least, that’s what Daddy used to think …

She felt slightly sick as she moved on to look at the other videos.

‘Niall Reakes’s alibi seems to hold up,’ Lightman told Jonah, after tapping on the door to his office. ‘His firm has sent over a few social media photos of the conference and forwarded on his flight bookings. He was on the twelve-forty home today.’

‘OK, thanks,’ Jonah said, reflecting that this would make things simpler. If Niall had been abroad, Louise alone had been responsible for moving Alex Plaskitt’s body, and quite possibly for killing him, too. But that didn’t mean that speaking to her husband was any less important.

Jonah braced himself for something of a confrontation, given Niall’s earlier blustering, but, in fact, the interview went smoothly. It was clear that Niall had burned off a lot of energy while he’d been waiting. By the time Jonah entered the relatives’ room, he was sitting meekly at the table, his expression mild and eager to please.

Jonah explained to him, briefly, why they needed to hold Louise. About the terms of custody and their application to the magistrate.