Quinn flicks the indicator and pulls the car over, parking half on half off the pavement so as not to stem the flow of traffic in this narrow artery.

‘Over there,’ says Stephen.

Archer sees a gathering of young people crowded under the bridge taking selfies and snapping shots of a painting on the wall.

‘Looks like his minions have beaten us to it,’ says Quinn.

They make their way toward the mêlée. Quinn shows his ID and barks at them to clear off.

A train rumbles past on the bridge above, shaking the ground below their feet.

Sprayed on the wall in shades of grey and black is a graffiti painting of a naked man dressed in a long scruffy coat. His hands are extended and cupped like a beggar, his beard wispy, his cheeks gaunt, his mouth open as if screaming in terror. On his chest are several skull tattoos.

Billy Perrin.

‘Jesus!’ says Quinn. ‘Our man certainly knew what he had in store for Billy.’

Using her phone, Archer takes three shots from different angles and turns to Stephen. His eyes are wide, his face seems paler than before.

‘Stephen, are you OK?’

He nods. ‘Who would do something like this? Billy was no saint, but he didn’t deserve to end up like he did.’

‘Show us where you saw the van.’

‘It was parked right here, on the side of the road.’

Archer looks up and sees CCTV cameras further down the street. She will get Os to check the footage.

‘Do you think you could come to Charing Cross Police Station with me and DS Quinn to make a statement on what you saw?’

Stephen hesitates and looks to the ground. ‘I don’t really want to.’

‘It would really help us, Stephen. You’ve seen the killer and he is going to kill again. You could help save lives.’

After a moment he replies, ‘OK.’

‘Thank you. I could look into getting you some accommodation for a bit, if you like.’

He smiles. ‘Can you do that?’

‘I’ll do my best.’

Back at the station, as Stephen make his statement, Archer calls Eula Higgins and arranges a place for him to stay at The Connection.

‘Luckily I have one room free and can squeeze him in there,’ says Eula. ‘How long for?’

Archer’s budget is tight this month but Stephen is a good kid and she will feel better if he’s off the street while this killer is still on the loose.

‘Five nights. Can you do me a deal?’

‘This isn’t the Hilton, Grace. We’re a charity.’

‘Understood.’

Eula sighs. ‘I assume this isn’t coming out of the police budget?’

‘I wish it was.’

‘He’ll have his meals and I’ll also add in free showers and laundry for the duration of his stay.’

‘Thank you, Eula. I owe you.’

‘No worries, Grace. Good luck finding this madman.’

*