She forced him to tell her the name of the man who had got him to kill her parents and before he died she cut off his penis and both his ears.

A week later Rosa walked into a bar in Camargo and put three bullets into the head of the gang boss who had ordered the hit on her parents.

After that she was snapped up by the Sinaloa cartel. She helped move drugs, committed robberies and got involved in kidnappings. But it was soon obvious that her real forte lie in killing people. She had a natural aptitude for it, and over time they started calling her The Slayer.

But she didn’t mind. In fact she found it rather flattering. And neither did she mind that behind her back she was also described as a psychopath.

It was true, after all. And it was no doubt why she enjoyed doing what she did.

And why she was so looking forward to what lay ahead in London.

11

Laura

The air of enthusiasm that had prevailed at the start of the day quickly evaporated. In its place there grew a stifling sense of foreboding.

The thoughts of everyone on the task force were dominated by the anonymous text message and its chilling warning.

As hard as I tried I just couldn’t get it out of my mind. The job we did was often a test of sanity, but I felt that we were now being tested to the limit.

At lunchtime word came back from the experts in the cyber-crime unit that they were unable to trace the source of the message, which was what we’d expected.

DCS Drummond also reported back on a brief conversation he’d had with the Commissioner.

‘His view is that we shouldn’t take it too seriously,’ Drummond said. ‘It isn’t the first time that officers in the Met have received threats of this kind and he’s sure that it won’t be the last. His advice is to be extra vigilant and at the same time raise the issue with those we interview as part of the investigation into Roy Slack’s mob.’

It was true that police officers were often threatened. Early on during the investigation into Harry Fuller, a man called my mobile and left a voice message threatening to rape me if I didn’t stop pursuing the gang boss. It gave me a shock, and I was dismayed to discover he’d used a burner phone so he couldn’t be traced.

But his threat just did not ring true so I didn’t lose any sleep over it.