Maria Rodriquez clearly wasn’t her real name and we’d probably find that she had entered the country on a false passport.

So what was her real name? Who was The Slayer? Was she a wife? A mother? How old was she? What made her become a killer in the first place? The questions were snowballing in my head.

Drummond came off the phone and said, ‘That was the office. British Airways have confirmed that a Maria Rodriquez was on flight 242 that arrived at Heathrow from Mexico City on Tuesday. We’ve contacted the Border Agency and passport and landing card details are being sent over.’

‘Tuesday was when we received the first text message,’ I said. ‘And the day before Dave Prentiss was shot.’

He nodded. ‘It’s looking like the risk you took in coming here is paying off, Laura.’

‘Let’s hope so, guv. I just wish we could get Carver to open up. He must know we’ve got him bang to rights.’

‘And that’s the problem. He’s afraid of digging a deeper hole for himself. I’m having him sent back to the Yard. He might be forthcoming once he’s talked to his lawyer.’

‘What about the word Bridges?’ I said. ‘We still don’t know what it refers to.’

‘The team are all over it. They’re checking roads, houses, firms and names. I’ve told them to get back to me the moment they get a sniff of something.’

‘So what do we do in the meantime?’

He waved his hand. ‘We turn this place inside out. See what else we can find.’

Within half an hour the house was packed with people. More uniforms arrived along with scene of crime officers and techies from the cyber-crime unit, who got straight to work on Carver’s smartphones and computer.

When I realised it was almost eleven o’clock I felt a sudden pang of guilt and rushed outside to phone the hospital. Thankfully Aidan was awake, having slept for most of the evening, and he assured me that there was no need to apologise for not calling sooner.

‘I’ve heard about the police woman who was shot tonight on the South Bank,’ he said. ‘They’re saying on the news that it’s believed to be the same killer.’

‘That’s right,’ I said. ‘It’s dreadful. But at least we’re closing in.’

I filled him in on what had happened, skipping the gory details, and he said he was proud of me for using my own initiative.

I would have carried on talking but a uniformed officer appeared at my side and told me that DCS Drummond wanted me to go back into the house.

‘I have to go, Aidan,’ I said. ‘Please try to get a good night’s sleep and I’ll see you tomorrow.’

‘I love you, Laura,’ he said.

‘And I love you too.’