‘DS Tripp has made some headway in the Berry case. The male on the Queensferry Bridge we’ve been referring to was captured on another onlooker’s mobile phone. We don’t have a clear facial view. He was wearing winter clothes, hood up, scarf on, but we’ve got the outline of his head. You’ll see from this footage’ – she took Graham’s former place at the laptop and selected a file – ‘that there’s a man shown in a rear view. He shouts encouragement at Stephen Berry to jump – we see his mobile phone held up at one point – and then he begins to laugh. Although we only have the rear view, the movement of his head matching the shouting of words and laughing makes us certain enough that this is the man we’ve been looking for.’

She closed the file and opened another one. An audio track began to play as the camera panned across a crowd. The words, ‘Go on, do it!’ could be heard clearly above the background noise, then a break, then laughter.

‘We had a speech recognition expert compare the two overnight. She’s confirmed that it’s the same man. We can’t place him at a crime scene, not yet, but we’re putting all of our efforts into identifying him. Tripp, I want your team pursuing media outlets to see what footage was posted of Janet Monroe yesterday.

‘We know the laughing man was filming, so let’s see if we can’t trace him through that. We’ll be able to exclude any innocent parties easily now that we have the speech pattern. We estimate that he’s in his twenties, roughly six feet tall. I saw him in the crowd yesterday but was unable to follow.

‘Assume he’s local and has a vested interest in potential suicides. It can’t be a coincidence that he appeared at two events in progress, so he’s either watching the media, or he has a contact – emergency services, possibly – who’s notifying him when a possible suicide is called in. Find him. Notify all progress to me immediately.

‘In the meantime, I’ll be showing the footage to Rune Maclure, the counsellor who assisted Stephen Berry on the bridge. I’d like results by the end of the day. If we can’t do this quietly, we may be forced to ask the TV stations to broadcast the footage to see if anyone’ll call in with a name, but that’s a last resort. If we do that, it’s a sure thing he’ll run.’

Ava closed the laptop lid and picked it up, making for the door. Pax Graham caught her as she went.

‘Could I have a word, chief?’

‘Can it wait? I’ve got Maclure waiting in my office and I know he’s got appointments to get to.’ She began to walk.

Graham fell into step at her side.