Drummond, who was standing next to me, pointed a rigid finger at Carver and said, ‘Were you sent to pick the woman up from the airport? Is that why you scribbled on the pad?’

Carver ignored him and raised his eyes to the ceiling.

‘What does Bridges mean?’ Drummond persisted. ‘Is it someone’s name or the name of a road or house?’

But the villain remained tight-lipped and was obviously determined not to say anything without getting advice from his solicitor first.

‘Get this piece of scum out of here,’ Drummond told the uniforms who were standing in the doorway.

His phone buzzed at the same time and he snatched it out of his pocket to answer it. The gaffer had made two calls in quick succession after I’d shown him what I’d found on the pad. The first had been to the office where the team were told to check out what Carver had scribbled on the pad. The second had been to the Assistant Commissioner who had asked to be informed of any significant developments. And this was most definitely that.

I placed the pad on the worktop and studied it again.

Maria Rodriquez

Flight BA242

Terminal 5

Bridges

I’d discovered through a quick online check that BA242 was a scheduled service that ran most days between Mexico City and Heathrow. It departed late at night and, with the time difference, arrived in London just after four o’clock in the evening the following day.

Officers were now onto British Airways to find out if and when a Maria Rodriquez had been a passenger.

It might not have been conclusive evidence, but my gut was telling me that Maria Rodriquez must be The Slayer, and that she had come here at the behest of Roy Slack.

In a way it made perfect sense because he wouldn’t have wanted to recruit someone who might be on the radars of UK and European law enforcement agencies.

It was my guess he had exploited his links with the Sinaloa cartel to enlist the services of a seasoned professional. Someone who wouldn’t flinch at the idea of killing police officers.

And the woman known as The Slayer fitted the bill. From what I’d read online she was the stuff that legends were made of.

Had she really killed more than fifty people? If so then she was obviously a bloodthirsty psychopath. And she clearly enjoyed what she did because she must have been doing it for years.

I was well aware of how bad things were in Mexico and how the sheer scale of violence and corruption was beyond belief. I also knew that the wars between the various cartels had encouraged a large number of people, mostly men, to become contract killers.

But it was still hard for me to understand how any woman could embark on a career that entailed slaughtering dozens of strangers.