Cheetham's eyes widened, though he kept the rest of his face under control. Clearly, he was one of those people whose eyes really are the windows of the soul. 'What about him?' he asked nervously.

'Well, my boyfriend and I have just bought an old house out in Heaton Chapel, and it needs a lot of work doing, and I noticed the van had a Stockport number on the side. I wondered if they specialized in that kind of job and, if they did, maybe you could give me their number? I tried Yellow Pages, but I couldn't find them,' I said.

Cheetham's mouth opened and closed. 'I… er… I don't think they'd be what you're looking for,' he gabbled. 'No, not for your problem at all. Old barns, that's what they do. Conversions, that sort of thing. Sorry, I… er… Sorry.'

Satisfied that I'd put the cat among the pigeons, as well as establishing Cheetham's guilt firmly in my own mind, I gave him a regretful smile and said, 'Oh well, when we do buy ourselves an old barn, I'll know where to come. Thanks for your time, Mr. Cheetham.'

An hour later, I was lurking behind a fruit and veg stall in the indoor market at Stockport. The bright autumn sunlight poured in through the high windows of this recently restored cathedral to commerce. It illuminated a fascinating scene. Across the crowded aisles of the market, in a little cafe, Martin Cheetham was in earnest conversation with none other than Brian Lomax, alias T.R. Harris.

Now I knew all I needed to know. All that remained was some proof.

I bought a couple of Russet apples and half a pound of grapes from the fruit and veg stall to keep my mouth occupied while I watched Cheetham and Lomax talk. Cheetham appeared to be both worried and angry, while Lomax seemed not so much tense as impatient. Cheetham was doing most of the talking, with Lomax nodding or shaking his head in response as he munched his way through a couple of barm cakes and a bowl of chips. Eventually, Lomax wiped his mouth with the back of his hand, leaned across the table and spoke earnestly to Cheetham.

There are times when I wish I'd learned to lip read. Or to predict the future. That way, I'd have been able to plant a radio mike under the table in advance. As it was, I was stuck in my less than blissful ignorance. All I could do was keep on Martin Cheetham's tail as he left the cafe and pushed his way through the shopping crowds back to the supermarket car park where he'd left his black BMW. A black BMW which I'd last seen parked outside Brian Lomax's house on Saturday night.

It wasn't hard to keep tabs on him. He drove back to Manchester like a man who's preoccupied with something other than the road and traffic conditions. Expecting him to go straight back to his office, I hung back a little as we neared the city centre, and that's when I almost lost him. At the bottom of Fennel Street, instead of turning left towards the Blackfriars car park where he'd been parked that morning, he turned right. I was three cars behind him, and I barely made it to the junction in time to see him turn left by the railway arches, heading for the East Lanes road. 'Oh, shit,' I groaned, stamping on the accelerator and skidding across four lanes of traffic in his wake. The Little Rascal really wasn't my vehicle of choice for a car chase. I only hoped the cacophony of horns wouldn't penetrate Cheetham's apparent reverie.

He wasn't in sight when I got to the next set of lights. I had to gamble that he'd gone straight on, out past Salford Cathedral and the university, past the museum with its matchstick men Lowrys, as reproduced on a thousand middle-class walls. I stayed in the middle lane, on the alert for a glimpse of his gleaming black bodywork. I was beginning to sweat by the time I passed the grimy monolith of Salford Tech. It looked like I'd lost him. But I stuck with it, and two miles down the East Lanes I spotted him up ahead, turning left at the next lights.

By the time I hit the lights, they'd just turned red, something I chose to ignore, to the horror of the woman whose Volvo I cut across as I swept round the corner. I gave her a cheery wave, then put my foot down. I picked Cheetham up a quarter of a mile down the road. He turned right, then second left into Tamarind Grove, a quiet street of between-the-wars semis, not unlike Alexis and Chris's. The BMW swung into the drive of a trim example of the type about halfway down on the left.

I drew up sharply in the little red van, keeping my engine running in case he was merely dropping something off or picking someone up. Cheetham got out of the car, locking it carefully behind him and setting the alarm, then let himself in the front door with a key. I drove slowly past the house and parked. I stationed myself by the rear door, keeping watch through the one-way glass of the window. I wasn't even sure why I was doing it. This had started off as a search for hard evidence of what Cheetham and Lomax had done to my friends. But I couldn't help feeling there was a lot more going on. What was Renew-Vations up to that sent Cheetham running down the road like a scalded cat to front up his partner in crime? And what was happening now? I have the kind of natural curiosity that hates to give in till the last stone is turned over and the last creepy-crawly firmly ground into the dirt. I kept coming back to the thought that whatever was going down here, Cheetham was the key. He knew I was poking my nose into his business. And Cheetham's partner in crime drove a white Transit van. Admittedly, the van in his drive at the weekend had been unscathed, but I figured it was a strong possibility that his business ran to more than one van.

If there's a more boring job than staking-out someone who's enjoying the comforts of their own home, I've yet to discover it. To relieve the monotony, I used my new toy to call the Central Reference Library and asked them to check the electoral roll for this address. Cheetham was the only person listed. Then I rang Richard to tell him my new number. This week, his answering machine featured him rapping over a hectic backing track, 'Hi, it's Richard here, sorry, but I'm out, leave your name and number and I'll give you a shout.' At least it was an improvement on the throaty, sensuous one he'd had running the month before. I mean, you don't expect to find yourself in the middle of a dirty phone call when it's you who's done the dialling, do you?

Then I settled down to listen to the play on Radio 4. Inevitably, five minutes before the denouement, things started happening. A white convertible Golf GTi pulled up outside Cheetham's house. A brown court shoe appeared round the driver's door, followed by an elegant leg. The woman Cheetham had called Nell emerged, wearing a Burberry. Her choice of car came as no surprise, though I've never understood the fascination the Golf convertible holds for supposedly classy women. It looks like a pram to me, especially with the top down.

Nell followed Cheetham's path to the door, and also let herself in with a key. Then, about twenty minutes later, a white Transit van turned into the street and parked a couple of doors away from Cheetham's house. Lomax got out, wearing a set of overalls like a garage mechanic, a knitted cap covering his wavy brown hair. He didn't give my van a second glance as he marched straight up to Cheetham's front door and pressed the bell. He only had moments to wait before the door opened to admit him. From where I was parked, I couldn't actually see who opened the door, but I assumed it was Cheetham.

I thought about sneaking round the back of the house to see if there was any way of hearing or seeing what was going on, but it was way too risky to be anything other than one of those tantalizing fantasies. So I waited. The plot was thickening, and I was powerless to do anything about it.