‘I think Ms McAndrew must have parked a row over from the outside of the car park. It looks to me like her car is just out of shot. As the bus drives by, I saw her walking up the space between the rows of cars, then she moves off to the side and out of shot. I’d say she’s walking quite fast. She’s got her head down because it’s raining. Next thing is, a few seconds later, another figure comes up the same way. I’d guess it’s a man, but it’s hard to be sure. He’s wearing a waterproof jacket with the hood up. You can’t see his face at all, except a bit of light glinting off glasses. He was carrying a case. Looked like it was made of aluminium, like photographers have. About the size of a pilot’s case. And he carried it like it was quite heavy. Anyway, he goes the same way as Ms McAndrew, only he speeds up as he gets closer. Almost running. You’d have to say he was following her. And then he disappears out of shot, right where she did. It’s not a lot of video. Only about fifteen seconds.’

‘You did well to get that, John. Now, how would you describe this figure? Was he tall, short? Build?’

‘Not tall. Medium height, I’d say. Not more than five feet ten. He was slim to medium build. It was difficult to tell. I couldn’t be sure how thick his jacket was. And like I said, he’s got his hood obscuring his face. The only distinctive thing is I think he might have a bit of a limp. It’s hard to be sure. The quality isn’t great and the weather doesn’t help.’

It was a tiny shred of corroboration, but Paula’s heart leapt at Okeke’s words. ‘That’s very interesting, John. Can you say which leg he’s limping with?’

He paused for a moment. She could hear him breathing. ‘I’d want to look again, to be certain. But I think the weakness was in his left leg.’

Bingo. Not that it was exactly a break in the case. But it would help if it came to issuing an appeal for witnesses. Unless the killer was smart enough to fake a limp to throw them off. They already knew he was forensically careful. If he suspected there was any chance of being picked up on camera, he may have deliberately chosen to create a false image. ‘I’m going to need you to make a formal report of this, John. File it with the incident room team, but send a copy directly to me and to DCI Fielding. I don’t want this to get lost in the white noise.’

‘Will do. You’ll have it within the hour.’