Don entered the deserted hallway and looked about him. On a plush leather chair sat a plush leather-clad secretary, reading something on a computer screen. She looked bored, like her day could be going a lot better than it was. Don walked over to the desk, deliberately not removing his sunglasses, although the lighting in the hall was poor. He cleared his throat and the secretary looked up, startled: she had obviously assumed she was on her own.

"Howard Madison?"

"He's not here right now," she said unhelpfully.

"That's not what my information tells me," he countered, trying to play it mysterious.

"What information would that be then?" She asked, barely interested. She scrolled down on the screen she was reading.

"FBI intelligence. Madison entered this building some time ago and hasn't left it since. Front or back entrance. So unless he can teleport, I want to see Howard Madison."

The secretary looked taken aback by his austere manner and glared at him as she touched an intercom. "Mr Madison, there is an FBI agent here wanting to see you," she paused and there was a silence before Don heard a voice come back "send him up."

"Fifth floor, third door on the right," said the secretary as she turned back to her computer screen, clearly determined not to give Don any more of her valuable time.

"Thank you very much," said Don as politely as could.

He did not hurry in the elevator on the way up; he didn't expect Madison to keep anything incriminating in his own office. Better to let him wait, if he was guilty, he would probably be wondering how Don had found him, if any of his associates had given him up, and how much the FBI knew.

Don knocked on the relevant door, which was labelled 'Mr H Madison, Chairman.' The man himself opened the door and smiled one of those superficial business-smiles.

"Do come in," he said, standing back and gesturing into his apartment in case Don was in any doubt as to which way 'in' was.

Don stepped in and removed his glasses.

"Now, what can I do for you agent?"

"Agent Eppes," said Don, not extending his hand. "I assume you know why I'm here, Mr Madison."

"Haven't the foggiest," said Madison cheerfully.

His charm act was doing nothing to improve Don's opinion of him.

"You'll have heard about the recent a spate of child kidnappings in the area," said Don, with a steely not in his voice, getting straight down to business. "I'm here to question you in connection with them."

The man's smile did not falter. Fake, Don found himself thinking. If this man was really just a happy-go-lucky entrepreneur, his smile would definitely have wavered at this news.

"In the area? If you're referring to those incidents in the paper – I thought we were safe – I thought they were only on the west side of town."

"You are safe Mr Madison.These scumbags prey on children, not grown men." Don did not trouble to keep the contempt out of his voice now.

"Indeed. Well then, what did you want to ask me?" He was playing innocent.

"First I want to know everything about your relationship with Rory Tubman. Then I want a detailed account of your movements for the past month. After that I'll decide whether to get a warrant to search your apartment, or whether to just arrest you on the spot. But you can start by telling me about Tubman; we'll take it from there." Don was speaking sharply now, nearly spitting the words out. He knew Madison was involved. There was something about the casual, cheerful exterior that smelt phony. This was the one.

"I used to know Rory Tubman on the buses years ago. We used to drive together on long shifts – you know, taking it in turns. I haven't seen Rory in oh – 6 – 7 years. But for the rest of it – I have no idea what you're talking about. If you think I had anything to do with any child-nappings, you're rocking the wrong boat. I'm a married man. I have 3 kids myself. You can't be a parent, Agent, or you would understand what every father goes through when one of his own kids so much as stubs his toe; I couldn't harm a kid. Look, I appreciate you taking the trouble to come to my office and everything, but if it's Tubman you're looking for, I can't help you."

In a moment the jovial exterior had vanished a new layer was visible. He was still docile, still composed, but there was an iron barrier beneath it all. He wasn't about to admit to anything. He was still relying on the fact that had Don had no evidence to link him to any crimes. Unfortunately, if he kept it up it was in danger of working. All Don had was an association that was nearly a decade old, and that wasn't anything like what he needed for a warrant, they both knew.

Don locked his gaze angrily for a second, but the tension was diffused by Don's cell phone ringing.

"Eppes," he snapped.

"Don? Its Charlie. Where are you?" He sounded vaguely excited.

"Charlie I'm in the middle of questioning a suspect," said Don exasperatedly.

"Madison? That's just it Don. I think I've found something! I've been going through Madison's company accounts, looking for any anomalies."

Don glanced up at Madison, who was wearing a relaxed 'can-I-help-you' expression.

"There's nothing obvious, but I think – I think you understand, I don't know anything, but I think –"

"Yeah Charlie, I get that part," interjected Don impatiently.

"I think I can see a pattern there. There are a number of small payments, made on consecutive days, in the run up to and days after a kidnapping. Obviously, there are plenty of small payments other times as well, but from the graphs I've drawn, there is a definite increase in frequency around the times of a kidnapping."

"Charlie, this is good, when can you be sure?"

"There are a few algorithms I could run if you like. It would probably be ready by tomorrow sometime."

"Charlie you're a genius – has anyone ever told you that?"

Charlie chuckled, said "bye" and rang off. Don flipped his phone closed and looked down at Madison, who had seated himself on a chair behind his deck during the conversation.

"You know who that was?" Said Don.

"Charlie?" Said Madison sarcastically.

"Yeah, yeah it was Charlie actually." Said Don, "Charlie is my brother and he also happens to be a brilliant mathematician and a consultant for the FBI. And you know what? Charlie is going to nail you for your little scheme you're running. You may not have left any physical evidence, Madison, but everybody leaves numbers."

"OK, right. Now I'm scared."

"Yeah? Well you'd better be, because I'm not going to stop until I have you and you're partner Tubman for what you're doing – so just keep talking."

"Agent Eppes? Do you have anything productive to say? Because if not I must ask you to leave. I am a very busy man – I have better things to do than be harassed for crimes I would not dream of committing." He stood up and strode around to the door and opened it. Don's lips were tight with anger as he passed Madison, but he kept his face otherwise impassive. He did not look back as the door closed, but walked into the elevator and pushed the down button.

Back in the apartment, Madison opened the cupboard door. It was a primitive hiding place, but it was the best they could do at short notice. Rory Tubman stepped out.

"Agent Eppes seems to be taking this personally," he said.

"You sound disappointed," said Madison.

"Trust me; I've met enough feds in my time. It's easier when they don't take it personally. The lack of sleep, the over-sensitivity, it just adds to their belligerence. Sometimes it takes months for them to get off your case. Of course, it can work in your favour as well. They tend to be so keen to pin you with something there's a chance they'll make the mistake of arresting you too early without the proper evidence."

Madison looked thoughtful. "What we really need is some leverage then. Something to make him keep his distance."

Tubman nodded pensively. "I didn't catch much of what he said in there. What idiot interior designer put a boiler right in a cupboard like that? Does the man actually have any evidence."

Madison shrugged. "Highly unlikely, otherwise he would have mentioned it. He knows we were friends, so I didn't see the point in denying it, but I claimed not to have seen you for 7 years."

"That was dumb – he can easily check you out on that."

"It's not a crime to pretend you haven't seen someone."

"I'm telling you Howard, Eppes is going to keep digging. The more he finds, the more he's gonna dig."

Madison bit his lip. "He got a phonecall. Said it was his brother. Reckons – get this, right – reckons his brother's a consultant for the FBI and is going to somehow use maths to prove we're involved."

Tubman did not smile back, but he did look intrigued. "He has a brother?" He said slowly. "How interesting. You know, I think we may have found that leverage we were looking for. Agent Eppes wants to take this personally? Its his call."

----------------------------------------------------------------------------------------------

A/N: Den, den, den . . .

Sorry for Don going all Horatio Caine-esque on you there, I just couldn't resist ;-)