He pauses. "Everyone says Robert was a very closed person," Richard says. "He was very sociable and charming, but after a conversation with him, you'd walk away realizing you'd learned nothing."

"What was Joanne like?" I ask.

"She was considered to be lovely and charming," he says. "A neighbor said that regular as clockwork she'd go blasting past the houses in a battered Porsche, taking the kids to school at five past nine. Everything was always chaotic."

I stop off at the local ironmonger's store, J W Kaye, to test Richard's story about Robert Hall leaving debts all over town.

"Yes, he owed me money," says Dave Earnshaw, who runs the place. "But it wasn't much, so I didn't think it was worth pursuing. He owed a lot of other people a lot more money than he owed me when he disappeared out of sight."

"To France?" I say.

Dave shrugs: "I suppose."

He reels off a list of failed Robert Hall businesses: a kitchen place in Dewsbury; a fitness center; an abandoned golf-resort project in Derbyshire; a company that imported cars from Europe and (illegally) adapted them from left-hand to right-hand drive; a disastrous Santa's grotto in the farmers' market in Hollowgate.

"He told Kirklees Council he was going to make it Christma.s.sy and lovely, like a fair," Dave says, "but when it opened, it was just a stall selling cheap plastic c.r.a.p."

When the council shut it down, Robert Hall smashed his way back in with a baseball bat.

MAN SELLING FESTIVE GIFTS IS CLOSED DOWN

... Security guards are patrolling the former Castle garage in Hollowgate and Robert Hall has been given until the end of the month to remove his property. Mr. Hall admitted he broke in and continued to trade for two days after the locks were changed by the council. Councilor George Speight, who chairs the council's markets committee, said, "In our opinion this was a market and not a fair."

-Huddersfield Examiner, December 1993

"He always had big plans that were always ..." Dave pauses. "Crumbling."

A FEW HUNDRED MILES south of the Chateau de Fretay, in the countryside near Cognac, Maria-Louise Sawyer runs a support group for British people who've moved to rural France to try to live the Year in Provencetype dream, only to find the whole thing spiraling out of control.

"It's the same story time and again," she says. And then-with a quite chilling fluidity-she tells me the "story":

"The French like to live in little tiny modern bungalows. When they inherit these big old properties, they don't want them. So they sell them cheap to the British. Back in Britain, the man was working, the lady was home. That was fine. They saw each other for only a couple of hours in the evening and at weekends. But then they move here. These are larger properties with grounds. So they're isolated. They can't speak the language. The man is possibly renovating an old property, but he doesn't know how to do it. Everything is different. You go to a government office, you don't speak French, you're an outsider. So he gets more and more isolated and resentful. He and his wife are together all the time. And they realize they don't like each other. They drive each other bonkers. They drink, because the drink over here is less expensive than water. And then ... bang."

Maria-Louise pauses. "That's what happened with my husband. He b.u.g.g.e.red off back to Britain after shredding all my clothes, daubing food over the walls, and leaving a note that said, 'I've gone.'"

THE DAY JOANNE HALL DIED, some neighbors saw her in the garden. It was the last sighting of her. She was pruning the trees and gardening-starting to plant the hundreds of seedlings in the plastic cups on the table that are still there but all dead now. The neighbors say she looked up at them and, with a big smile, waved.

"I've Thought About Doing Myself in Loads of Times ..."

Maesbrook, Shropshire, is a beautiful, well-to-do village on the Welsh border. The houses are vine-covered Georgian mansions. The cars parked in the driveways are Range Rovers and Porsches. The people of Maesbrook are, by and large, self-made millionaires from Birmingham and Wolverhampton, entrepreneurs who've made it big.

"I'd love to live somewhere like this if I could afford it," I think ruefully as I drive through the village, closely tailed by a police car. The police have been following me ever since they spotted me reading the condolence bouquets on the road outside the grand Osbaston House.

On August 26, the mansion's owner, Christopher Foster, returned from a neighbor's barbecue and meticulously destroyed everything he owned. At some point he made the decision to include his family in that. He shot his wife, Jill, in the back of her head in their bedroom. He did the same to his fifteen-year-old daughter, Kirstie, in her bedroom, interrupting her as she chatted with friends on Bebo. He shot the horses and the dogs, and he jammed a horse trailer against the gate and shot out the tires, presumably to stop potential Good Samaritans from intervening. He flooded the mansion with oil, set everything on fire, and then shot himself. A few hours later, the bailiffs arrived, unaware that the possessions they were supposed to impound that day no longer existed.

"From a neighbouring family-absolutely stunned," read one bouquet. "You were all such a lovely family," read another.

According to his friends, Foster adored his family in a very ordinary way. He was apparently forever seen laughing and joking and cuddling them while watching TV and so on, right up until the night he murdered them.

I read the condolence cards for a few minutes and then a policeman pulls up.

"Can I help you?" he asks.

I show him my press card.

"You look too scruffy to be a journalist," he says.

We both laugh. Then I bid him farewell and drive away. Now the police are following me, past the gated mansion belonging to John Hughes, the millionaire luxury car dealer whose barbecue and clay-pigeon shoot the Fosters attended a few hours before the murders; past their local pub, the Black Horse Inn; and toward my meeting with Foster's friend and blacksmith, Ian.

Had this been a working-cla.s.s double murder-suicide, I don't think the police would have bothered following me all the way out of town, but Maesbrook is a rarefied, aspirational village, and they seem to want to make absolutely sure I've gone.

Once I'm out of the village limits, the police car turns around and I make the final part of the journey alone. Ian lives in Meifod, Powys. He's a friendly, welcoming, shaven-headed man with five horses and eleven acres. We sit in his kitchen. He makes me a cup of tea and says he keeps remembering a weird incident that occurred a month before the murders.

"Before I explain what it was," Ian says, "let me tell you something about Chris Foster. He was always busy, messing with the horse trailer, cleaning it, fixing this or that, taking out trees. He was always home. I did wonder why he wasn't at work. I knew he was something to do with oil, and everyone called him 'the Millionaire,' but he was always home. He kept his barn spotless."

"That's weird," I say, in a dark chuckle, "to keep a barn spotless."

"I keep mine spotless too," Ian says.

"Oh, well, not weird ..." I say.

"Let me show you my barn," Ian says. "And then I'll tell you about the weird thing that happened a month before the fire."

On the way to the barn I tell him what I've learned about why Foster was always home. In 1997, he had a eureka moment. He invented, and patented, a new chemical formula.

"It came to him in a flash," said Terence Baines, who'd been his accountant back then. I had phoned Terence shortly before leaving for Shropshire. "Before then, he was just an ordinary bloke from Wolverhampton," Terence said, "a salesman living in Telford, working for some company that went bust. But one day he suddenly thought, 'Hang on. If I get a bit of this and a bit of that, a bit of special rubber and plastic, and put it all together, it'll make a new type of oil-rig insulation.'"

Foster called his invention Ulva Shield. It won an apparently fantastically rare A1 fire-test rating. Where other oil-rig insulations burst into flames, Ulva Shield just formed a safe, crisp sh.e.l.l. The big oil companies began placing orders.

"The company went great guns," Terence continued. "Chris started dressing very smartly. He wanted to present himself well. He liked good holidays, a decent car ..."

Actually, he bought a fleet of decent cars-two Porsches, an Aston Martin, a 44 for his wife (with the license plate JILL 40), and a tractor for the mansion, Osbaston House, that he'd bought in Maesbrook. He was doing an extreme version of what an awful lot of people were doing back then: living on credit, believing the boom would never bust. "He never planned on what things would be like when he was sixty-five or seventy," Terence said. "It was always 'What can I do now?'"

Along with the mansion and the cars, there were the affairs. Foster had at least eight mistresses, according to Jill's sister, Anne Giddings. "He had a big thing about blondes," Giddings later told the Sunday People. "Jill knew all about his affairs. There were lots of women on the scene. But she played the dutiful wife and kept quiet. He wasn't a good-looking guy, but money did the talking. He was always flashing the cash-it seemed to give him confidence."

But then it all went bust. In 2003 Foster contracted a supplier, DRC Distribution, to manufacture Ulva Shield exclusively. But by 2005 his liabilities were 2.8 million higher than his a.s.sets, presumably because he'd spent so much on mansions and Porsches and guns and membership to various fancy clay-pigeon-shooting clubs. In desperation, Foster sourced a California supplier who could manufacture Ulva Shield cheaper. DRC found itself lumbered with a warehouse full of Ulva Shield it couldn't sell because it was patented to Foster. DRC sued and won.

At the Royal Courts of Justice, on February 28, 2008, Lord Justice Rimer said Foster was "bereft of the basic instincts of commercial morality. He was not to be trusted." And so it all came crashing down. DRC took control of the Ulva Shield patent. Foster may have been lacking in commercial morality, but he certainly knew how to invent a good new fireproof chemical formula. Under DRC's less flashy stewardship, Ulva Shield has become a huge deal in the oil-rig world, supplying to Exxon, BP, Sh.e.l.l, and thirty-nine other giants. Foster, meanwhile, suddenly found he had nothing to do but stay home and look after the horses and the fifteen acres.

We reach Ian's barn. It really is spotless. The hay is as smooth as a freshly made bed at a posh hotel. "Our horses are our lives. They're everything to me and the children. I'm going through a divorce at the moment-"