Thanks to me Roy Slack was gone and his hired assassin was under arrest. There’d be no more threats. No more murders. Their reign of terror had been short-lived, but it had been devastating. Five dead. Six if you included my child. Two wounded. And many lives destroyed.

As I stood there being gawped at by strangers I felt a tide of emotion rise up through my body. I couldn’t believe that it was over. The threats. The shootings. The bloodshed. The abject fear that had gripped us all.

I wanted to cry. To let it all come pouring out. But I forced myself not to, and instead sent a text to Aidan and my mother in which I wrote: At last it’s over.

When Drummond arrived on the scene he was full of praise for what I’d done.

‘You’ve played a blinder, Laura,’ he said. ‘We’ll probably never know if she would have carried on killing but at least we do know that now she won’t be able to.’

I asked him if he had spoken to Alice Green, the woman who had tipped us off.

‘I’m calling on her next,’ he said. ‘You should go home or to the hospital to be with Aidan.’

But curiosity got the better of me and I insisted on going with him to interview her.

Alice Green was in pieces when we arrived at her apartment and I felt sorry for her. She told us how she had met the hot Latina chick at a West End club and how they’d fallen in love with each other.

‘I know it was ridiculously quick, but it was real,’ she sobbed. ‘She seemed so kind and so … normal.’

Alice confirmed that they had spent last night together on the South Bank and that Maria had sneaked off to shoot the police officer.

‘I swear I had no idea what she was going to do,’ she said. ‘She gave no clue, even after she did it. She joined me in the pub and then we had dinner. And I had no reason to suspect that anything had happened. Or that she was carrying a gun in her bag.’

It was such a sad story that I found myself fighting back tears. I wondered if The Slayer had really meant it when she told Alice that she intended to leave Mexico and move to London. Or had it merely been a cruel lie just so that she could have a sexual partner during her stay here?

It was one of the questions that we would put to her in the days ahead, along with what her real name was and who else she’d been in contact with since arriving in London.