The safe contained an Apple iPad, three passports, two wigs, a key on a ring and a white envelope.

The passport photos were all the same and of an attractive woman with long black hair. But there were three different names, one of which was Maria Rodriquez.

I had to admit she was a stunner. She reminded me of those hot Latina girls who often graced the covers of fashion magazines. She had soft features, olive skin, full lips and sultry eyes. It was beyond me why someone lucky enough to be so beautiful would choose to become a contract killer.

And the evidence to prove that she was indeed the woman we were looking for was laid bare on a sheet of paper inside the envelope.

It was a typewritten list of names, addresses and contact details of all the detectives on the organised crime task force, along with many of our relatives, wives, husbands and partners. My name was there and so was Drummond’s. And there were ink lines through two of the names – Dave Prentiss and Marion Nash. However, the Commissioner’s name wasn’t on the list and I wondered if it had been added as an afterthought.

Also, there was nothing to indicate who the next victim was going to be.

‘I’m assuming this was provided by the mole inside the Met,’ I said. ‘It’s terrifying to think that she was planning to work her way through it.’

At the bottom of the list was a web address. Drummond opened up the iPad, which wasn’t locked, and typed the address into the search engine.

What appeared shocked us both. There were several pages of photographs of most of those on the list, including me, Drummond, Aidan and my mother. It seemed they’d been copied from various social media sites and in the case of some of the detectives, from newspaper features.

The iPad also revealed that she had used Google Maps to check out the addresses, including my home in Balham. It was all very disturbing. I had to close my eyes and will myself to think clearly.

‘There’s still nothing to link the bitch to Roy Slack,’ Drummond said. ‘Except Danny Carver.’

‘I reckon this is enough to be getting on with, guv,’ I said. ‘Evidence will turn up, I’m sure.’

The investigation had taken a huge leap forward. The assassin was still out there, perhaps stalking her next victim, but we knew who she was. And what she looked like.

‘Why do you think she has this?’ Drummond said, holding up the key ring from the safe.

The plastic fob enclosed a photo of the outside of a pub and the words Three Crowns, Vauxhall.

The name rang a bell with me. ‘We drove past that pub on the way here, guv. It’s about two hundred yards along the road.’