Although he'd been arrested once by Met officers, in early 2001 on suspicion of murder, Hook had somehow avoided getting charged. Since then he'd kept an extremely low profile, and it was known that he'd resorted to plastic surgery on a number of occasions in order to change his appearance. So determined was he in this that hardly any of the people Bolt's team spoke to could physically describe him adequately (let alone say where he might be found). Those few who did attempt it came up with wildly different versions, none of which bore much resemblance to the badly scarred young man with the skin graft on his chin who appeared in the police mugshot taken when he was arrested in 2001.

Armed with all this information, the authorities had put out an all-ports alert for Hook and had every police force in the UK looking for him. But as the days turned into weeks, it became clear that he'd slipped the net, and eventually the public outcry died down as other heinous crimes vied for their attention.

Bolt, though, had never forgotten twelve-year-old Leticia Jones, a pretty little thing with a big gap-toothed grin who looked younger than her years. When, two years later, there was a series of high-level contract killings in southern Spain, including the murder of a Russian businessman in his Marbella villa along with three of his bodyguards, Bolt had suspected Hook's involvement. Whatever people might think, professional contract killers are few in number, ones capable of taking out four people at a time even fewer. Bolt had informed Interpol, and sure enough his hunch had paid off. A month later Hook was apprehended on a European arrest warrant as he boarded a plane at Madrid airport travelling under a false passport. Even the master of disguise could do little to conceal the fact that he was missing two fingers.

Less than a week later, Bolt and five colleagues from the NCS had flown out to Spain to bring him back to face trial for murder; but before they'd even touched down news had come through that Hook had escaped from custody, killing a police officer with his own gun in the process.

Hook was never seen in public again. Even though his name was high on Interpol's most wanted list, he disappeared completely. There was the occasional reported sighting, as well as daring contract killings carried out in different parts of the world which may or may not have borne his hallmark – a senior Indonesian politician slaughtered with his whole family; an American oil billionaire who'd disappeared off the face of the earth while on a hunting trip in the Yukon along with his son and two-man security detail, leaving a trophy wife thirty years his junior to inherit a fortune – but never anything concrete.

And now, three years on from his arrest in Spain, he was back again.

The first question was, why?

The second was what had happened to the woman who photographed him, and it was this one that Bolt was particularly concerned about as he sat in his boss's office at six o'clock that evening telling him about the Hook sighting. Because Tina was still out of contact.

It had to be said that SG2 Barry Freud, the SOCA equivalent of a DCS, was not best pleased with what he was hearing. A big, bald Yorkshireman with more than a passing resemblance to Humpty Dumpty, Big Barry, as he was universally known behind his back, constantly had one eye on promotion and as a consequence liked to run a steady ship, with risk-taking kept to an absolute minimum.

Usually Bolt could tolerate this type of environment (although he didn't particularly like it), but today things were suddenly very different. 'We can't just sit here, sir,' he said urgently. 'Hook's been on SOCA's most wanted list right from day one, and now we've had a sighting of him back in the country. We need to be putting all the resources we can into looking for him.'

Big Barry rolled his eyes and leaned back precariously in his seat. 'We've just spent half the day in a bloody great meeting with the FIU-'

'Which got us nowhere.'

'And we're right in the middle of a long-running case,' he continued, ignoring the interruption, 'against an extremely high-profile target.'

'You don't get much more high profile than Hook, sir. Ex-IRA gunman turned contract killer who murdered a twelve-year-old girl on one of his jobs. It would be a coup if we got him,' he said, appealing to his boss's ambitious streak.

Big Barry didn't look convinced. 'But where are we going to find him? That's the problem. We don't know when or where these photos were taken, do we?'

'No, but-'

'And you said Tina Boyd sent them to you?'

'That's right.'

'I thought she was back in the Met. Why's she sending them to you?'

Bolt told him about her call the previous day and the kidnapping case she was investigating.

'It all sounds bizarre, old mate,' he said, pulling a face. Big Barry Freud called every man he knew 'old mate'. It was supposed to be a term of endearment, but always sounded vaguely condescending.

'Bizarre it might be, but Tina's missing. And she has been since soon after she took those photos. Her mobile's off and we're still trying to trace where it lost power. And we're using the ANPR to try to find her car,' Bolt added, referring to the automatic number plate recognition system, a nationwide network of cameras used for tracking car movements.

'So you've already got people working on this? You haven't got the authority to do that, Mike.'

'Tina was one of ours for over a year, sir. Trying to help her is the least we can do. And if it helps us track down Hook, then we'll get a double result.'

'Have we got anything so far?'

Bolt sighed. 'Not much yet. I've got an all-ports alert out on Hook and the team are all chasing down their informants, seeing if any of them have heard anything on the grapevine about his return, and what he might be here for. Because one thing's for sure: it's not going to be a social visit.'

'What about the kidnapping Tina was meant to be investigating. Any leads on that?'

Bolt shook his head. 'I didn't write anything down when she phoned me about it. And it seems she was working on it unofficially. I spoke to Islington CID, where she's based now, and they've managed to get me the crime report that Tina filled out. It's not very detailed but it's got the name of the man who reported the kidnap initially: Robert Fallon, an unemployed thirty-four-year-old from Colindale. But he's not answering his home phone, and if he owns a mobile then it's pay-as-you-go because there's nothing in his name.'

'This isn't very promising,' said Big Barry with a marked lack of enthusiasm.

Bolt wasn't deterred. 'Tina also took a photo of a Toyota Land Cruiser which we think is connected to Hook, and we've got the ANPR people looking for that as well. We've got a lot of balls in the air and we only need one or two of them to come down for us to solve this.'

Big Barry Freud leaned forward in his seat, resting his elbows on his huge slab of a desk. 'All right, old mate,' he said, giving Bolt a suitably serious look. 'Because you've had results before, I'm prepared to cut you some slack. If any of these leads turn up something then we'll concentrate resources on trying to find Hook. It looks like we're already doing what we can to find Tina. But I can't just pull the whole team off what they're doing and send everyone off on a wild goose chase. And if you've put an all-ports alert out for Hook, then we've already done our bit. You understand where I'm coming from, don't you?' he added, his tone suggesting that he believed he was being hugely generous in his offer.

Bolt knew there wasn't much point saying anything else. It was the best he could have hoped for from his boss, so he said he'd keep him posted and headed back down the corridor to where his team were still flat out working to find their former colleague. Tina had never been hugely popular during her time at SOCA, mainly because she'd kept herself to herself and avoided social gatherings, but she was respected by everyone for her skills and determination, and there wasn't one person in the team who wasn't desperate to find her.