‘Maybe he likes to speak really softly,’ said Lesley.

‘Where do you even buy a bat that size?’

‘The Big Bat Shop?’ said Lesley. ‘Bats R Us?’

‘Let’s see if we can get a look at his face,’ I said.

‘Plus Size Bats,’ said Lesley.

I ignored her and clicked forward. The murder took less than three seconds, three frames: one the wind-up, two the blow and three the follow-through. The next frame caught Smurf Hat mid-turn, his face in three-quarter profile showing a jutting chin and a prominent hook nose. The frame after showed Smurf Hat walking back the way he’d come, slower than the approach, casual as far as I could tell from the stuttering image. The bat vanished two frames after the murder — again, I couldn’t see where it had gone.

I wondered if we could enhance the faces, and started looking for a graphic function I could use.

‘Idiot,’ said Lesley. ‘Murder Team will be all over that.’

She was right. Connected to the footage were links to enhanced pictures of William Skirmish, WITNESS A and the murdering gent in the smurf hat. Contrary to television, there’s an absolute limit to how good a closeup you can extrapolate from an old-fashioned bit of video tape. It doesn’t matter if it’s digital — if the information isn’t there, it isn’t there. Still, someone at the tech lab had done their best, and despite all the faces being blurry it was at least obvious that all three were different people.

‘He’s wearing a mask,’ I said.

‘Now you’re getting desperate,’ said Lesley.

‘Look at that chin and that nose,’ I said. ‘Nobody has a face like that.’

Lesley pointed to a notation attached to the image. ‘Looks like the Murder Team agree with you.’ There was a list of ‘actions’ associated with the evidence file, one of which was to check local costumiers, theatres and fancy-dress shops for masks. It had a very low priority.