Dan Waddell - The Blood Detective

Nigel nodded absent-mindedly - he'd switched off, wanting to be left alone to plan the rest of his research. He looked up and saw Heather weaving her way through the lunch crowds. Duckworth spotted her, too, and scuttled away. She watched him leave, lip curled.

'What did that creep want?' she asked.

'Just poking his nose in,' Nigel replied. 'Goes with the job.'

'He's an oil slick,' she shuddered. 'The team have the Dart list. They've started working down it one by one.'

'What about the Fairbairn list?'

'Nothing so far. Couldn't get much sense out of Foster. He sounds knackered. Told me he managed to grab a few hours' sleep at his desk last night, first he's had in three days. I told him to go home and get some rest, but he blustered. At this rate he'll probably end up keeling over.'

Back at the indexes, Nigel turned his attention to Detective Henry Pfizer. The surname was soon explained: he was born in Berlin, then part of Prussia.

It seemed he left the country of his birth as a young man, escaping the turmoil and upheaval that permeated many parts of Europe in 1848. England was a safe haven. Henry had met and married a London girl, Maria, and they had a son, Stanley. Much of this he gleaned simply from the 1881 census. He turned next to the 1891 census, but there was no sign of the family. A glance at the death indexes yielded no explanation either.

Nigel pulled a battered address book from his bag and found a number for a German genealogist he'd asked to carry out research for him in the past, usually tracing the roots of those who had emigrated from what was now Germany. He made the call, asked him to check records from 1881 onwards for Henry or Heinrich Pfizer and his English wife and child, making it clear that he would pay well for a prompt response.

The dead end frustrated him. They always did. The challenge came in overcoming such obstacles. You needed to think laterally, follow a hunch. He would return to Pfizer later; first there was Joseph Garrett.

This one was straightforward. He managed to tear through the generations. The two World Wars took their toll on the males in the Garrett line, and the name almost died out in the 1960s. But he managed to locate five living descendants.

He was listing their names when the call came through from Germany with results of a preliminary census search. No records of any Pfizer of that age, or any with an English wife, on German censuses.

He had not returned to the land of his birth.

Foster was dying on his feet as the day wore on. He stalked up and down the incident room, manically running his hand back and forth over his head. Coffee no longer had a galvanizing effect. All it did was make his head and eyes ache. He felt the old craving for nicotine. During times like this, when sleep was in scarce supply, he would chain-smoke his way through the exhaustion. Now there seemed to be no repelling it. Harris had told him to get some rest, but there were a few things he needed to do first.

Patricia MacDougall, the fourth victim, had last been seen on Sunday afternoon, walking her dog in Holland Park, something she did every day, though usually in the evening. She had been seen drinking a coffee and smoking a cigarette outside the cafe mid afternoon. She paid and left. No one had seen her since. A team had been blitzing the park since yesterday, accosting every parkgoer with pictures of her and the artist's depiction of the man seen drinking with Nella Perry in the pub. But no one had seen her leave and no one had recognized the suspect. The dog had also vanished. Foster didn't bet against it turning up dead on someone's doorstep at any second.

Nigel Barnes had begun filing the first batches of descendants' names. With the help of Andy Drink water, Foster had sketched out a condensed family tree for the Fairbairns, Darts and Garretts on the whiteboard, their names on the top, lines leading down to each of their living descendants. Those who had been spoken to on the Fairbairn list were marked, as were those whose movements were deemed worth following for the next twenty-four hours. There were still seven descendants to be contacted. None of those they had located matched the fingerprints found at the scene.

As for the descendants of John J. Dart and Joseph Garrett, Foster had decided to put a car outside the house or place of work of each likely victim and follow them for twenty-four hours, without them knowing. Informing them there was a possibility they might be the next victim of a serial killer would create understandable panic. The whole operation yoked together hosts of officers from other investigations and other departments, but Detective Superintendent Harris, scared witless by the mocking of that morning's press, was willing to offer Foster all the support he needed.

As Foster scratched an innocent Fairbairn name from the list, Drinkwater approached him.

'Another one bites the dust,' Foster said, wearily.

Only six Fairbairns were left outstanding. Was the killer among them or was Foster heading down a cul-de-sac?

'What do you want, Andy?'

'Sir, forensics say they've found some DNA on the last victim. On her clothes. Seems the effort of getting her up the stairs to the flat caused him to sweat. They found drops on her shirt.'

This perked Foster up immediately. The pace was beginning to tell; the killer was getting sloppy. Making mistakes he had avoided earlier in his spree, becoming too ambitious.

They had a link. He got in touch with forensics and asked someone to get along to the Hunterian Museum and get a sample from the skeleton of Eke Fairbairn. If it matched the killer's, then the theory that it was one of his descendants was on the money.

His phone went. Heather Jenkins, filling him in on what they had discovered that morning at the FRC.

'Pfizer has disappeared from the records,' she told him. 'Every mention of him and his wife and child.'

Foster cursed their luck. Of all the protagonists in the 1879 case, he felt fie was the one who deserved the most opprobrium; perhaps the killer felt the same.

Part of Foster hoped the bent bastard's conscience had got the better of him, that he'd left his clothes on the beach and walked into the sea, never to be found. But that didn't explain why his family had vanished, too.

'Tell Nigel to keep working on it,' he told her.

'Wherever he wants to go, whichever archive, it's open for him.'

Foster and Drinkwater arrived at a draughty community hall in Hounslow as the light started to ebb from the day. Foster felt so tired that putting one foot in front of the other was an effort. After paying a visit to the West London Family History Society he vowed to get some sleep. Everyone was in place; they would watch the suspects and their potential victims all night. Each inch of Powis Square had already been searched and was under surveillance. For the first time they appeared to be a step ahead of, not behind, the killer, though it made Foster feel uneasy. Did he have one final sleight of hand?

Inside the hall the air was cool, wintry even. Yet there were rows and rows of people sitting down, a sea of white hair bearing out John Fairbairn's claim that few of his fellow members were below retirement age. Fairbairn, seated in the middle, saw them enter and gave a wave. Foster nodded back. At the front a tall, elderly gentleman in a knitted cardigan was giving a talk, referring to diagrams on an overhead projector.

He and Drinkwater stood at the back and listened, waiting for the man to finish so they could begin the task of collecting everyone's prints.

The voice was flat, without tone. Just listening made Foster's head feel heavy. At first, the words washed over him. But then, to keep himself awake, he tuned in to what the man was saying.

'Those who know nothing of history, who are ignorant of the sacrifices made by others to build their country and their family, have no appreciation at all of the struggles and sacrifices involved in making and building something that will last. History gives us a sense of proportion, of the longer view of things.