Gillard’s wish to learn a bit more about the first victim was answered sooner than he had expected. The detective chief inspector was still sitting at his desk at 6:45 p.m. the same day when an email arrived in his in-box, headed ‘missing persons’ and written by the chief international liaison officer at Taipei police HQ. There, in excellent English, was a list of the several thousand male Taiwanese citizens who had bought air tickets to London since March. The liaison officer had helpfully flagged up those who had already returned, which left 485. Even more useful was the appending of the date of birth of each person, based on passport details. That allowed Gillard to exclude those who were clearly too young or too old to be the man they had found. Leaving a wide age window of 40 to 65 gave them 117 citizens. The officer apologised profusely for not yet having linked the supplied list to those who had been reported missing but promised it for the next day.

DC Hoskins came over to see what his boss was so excited about. ‘That’s fast,’ he said. ‘We haven’t got an answer from the Border Force yet about who arrived in Britain.’

‘Well, we can help them,’ Gillard said. ‘Send Border Force those 117 Taiwanese passport numbers, see which of them did indeed arrive and how many have left. I want it by tomorrow morning. I’ll ring Rigby at home to see if she can add her authority to it.’

Chapter Twenty-six

Friday

By the time the main incident room meeting was convened the next morning a lot more information had arrived. Only one of the Taiwanese travellers had been reported missing, and that was quite recently. He was Dr Wei-Ling Chen, a well-known academic in the field of nanotechnology who was supposed to be attending a conference in Oxford early in June.

He had never checked in.

Gillard had appended printouts of everything he’d received from Taipei, and the confirming information from the Border Force onto the whiteboards that had for so many days only had speculative information scrawled on them. ‘Hopefully, we can make a very quick breakthrough on this,’ Gillard said. ‘Dr Chen was reported missing by his sister just a couple of weeks ago. She said that her brother had been depressed and might not have caught the plane to Britain at all. In fact, as we can see here, he did arrive at Heathrow on June seventeenth.’

‘Do we have a mobile phone number for him?’ asked Rob Townsend. ‘That would be the quickest way of checking where he went.’

‘Yeah, way better than trying to wade through CCTV cameras at Heathrow,’ muttered Hoskins.