Five minutes later, they watched as the old lady hobbled out of the front door and down the path, shaking her head. She was carrying a large bag. As she reached the pavement, she turned and gave them a stiff-armed, clenched fist salute, then stamped off along the street.

‘Nice,’ said Desmoulins. ‘Very nice. We deal with such a sophisticated clientele.’

As soon as Maurat joined them, Rocco headed back to Amiens, mulling over what the driver had told them. If what he’d said was true, it meant Lambert – or someone like him – was bringing in illegals to work on the cheap. No papers, no insurance, no tax, no records. And plenty of cheap replacements if anything went wrong. As he’d also said, it was happening all over, and was probably the tip of the iceberg.

What it didn’t explain was why one of the men had been killed in the truck, and why one of them – a woman – had disappeared before reaching their destination.

By the time they got back to Amiens and booked Maurat into a cell, it was too late to do anything productive, so Rocco decided to call it a night. His plan the following morning was to brief Massin about Maurat’s story, so that the commissaire could organise an investigation of the pipeline and smooth any ruffled feathers with the Saint-Quentin police. He also wanted to take a walk along the canal where the body had been discovered. That might yet yield up some fresh ideas about what had happened there.

As it turned out, the canal walk was more imminent than he’d planned.

Just as he was turning to leave the station car park, the young night duty officer jogged out and tapped on the side window.

‘I almost forgot, there was someone asking for you earlier, Inspector. By name. Said it was urgent, but she wouldn’t give any details. I thought you might know who she was. She looked stressed, apparently.’

‘What did she look like?’

‘Can’t say – I wasn’t on duty then. The desk sergeant said she was quite a looker, although a bit … on the dusky side, if you know what I mean.’

Rocco bit back an instinctive reprimand. It wasn’t the younger man’s fault, and tearing a strip off him would serve no purpose.

‘Was that all?’

He handed Rocco a slip of paper. ‘She left this.’

Rocco thanked the officer and headed home.

The description of the woman, skewed as it was, would have meant nothing by itself. But the words scribbled on the piece of paper gave him a good idea who she might be.

The canal, go west of the village where we met. 10.00 tomorrow.

CHAPTER TWENTY-THREE

It was 09.30 the following morning when Rocco stepped onto the parapet over the canal where Claude had found the piece of cloth. He was early through long habit. Being early meant you weren’t on the back foot, giving someone else the advantage. Being early allowed you to control your approach and tactics, not be controlled by the actions and plans of others.

He looked both ways along the water. Behind him lay Poissons, about a kilometre away. In front was Amiens, distant and over the horizon, more kilometres than he would care to trudge. The canal banks were deserted and still, the water in between a dark-grey ribbon of coldness, barely moving.

On the far side of the canal was a towpath, where horses and men had once used muscle power to move the barges along. It was now overgrown in places, used mostly, according to Claude, by fishermen who looked more for solitude and the occasional tickle rather than the combat of challenging waters and bigger fish who could fight back.

He dismissed taking the path back towards Poissons; instinct told him he was meant to follow the towpath to the west. But why so coy – even secretive? Would it mean something to anyone else who saw the note? Or was she playing a game with him?

He looked towards Amiens and remembered what Maurat had said about giving directions to the illegal immigrants. ‘… cross the canal to the rive nord and turn left.’

Left was west.

He stepped onto the towpath and stopped. Heard a crackle of movement in the undergrowth among a belt of tall, spindly maples heavy with tangled wind-felled branches.

‘Call yourself a hunter?’ he said calmly. He avoided looking towards the trees in case anyone else was watching. ‘My grandmother could move more stealthily than that.’

A dry chuckle drifted out of the treeline. ‘Pity she’s not here, then, isn’t it? I could still be tucked up in bed.’ It was Claude Lamotte, waiting where they had arranged earlier that morning. Claude knew the area well and was going to shadow Rocco along the canal, staying well back in cover. If this was some kind of trap, it would be useful having Claude watching his back.

‘Take it at an easy pace,’ Claude continued, ‘so I can keep up and check ahead. If I shout, hit the ground immediately and stay down.’

‘Got it.’ Rocco nodded minutely. Claude had briefed him on the kind of terrain that lay ahead; it was towpath all the way, some clear, some overgrown, bordered by trees and thick bushes. No buildings, no houses. There was an abandoned barge about two kilometres away. Canal traffic was unpredictable but mostly quiet.

He began to walk at a steady pace. As a former soldier, he regarded walking as a simple mechanism for getting from A to B. It gave him no particular pleasure, and stopping to admire the scenery along the way had never been much of a priority. In any case, right now, the cold coming off the water was enough to blur any scenery and make him duck his head into his coat collar.

He ignored the discomfort and focused on Nicole instead, wondering whether he was walking into something bad. She hadn’t looked like someone running anywhere, nor had she looked like any illegal workers he’d seen before. She wore good-quality clothes and even had a car, which Gondrand had admitted she’d bought with cash. It was hardly the economic hardship normally faced by those wretched enough to be travelling from one country to another by underground channels.

Yet it was the only explanation that tied her to this place and to Poissons. There was no other that he could think of.

But why come looking for him at the station? He’d told her he was a cop, which usually killed any personal interest stone dead. Either she was totally on the level, and had a problem only a cop could fix … or she was an illegal and prepared to bluff it out for whatever reasons he had yet to discover.

After walking for what he judged was nearly a kilometre, he still hadn’t worked it out.

Then he saw her.

She was sitting back from the canal on a stack of heavy timber pilings. She was wearing the coat he had first seen her in, but this time her head was bare. She looked wary, as if she, too, was having doubts about the sense in having this meeting in such a remote spot.

Rocco turned to look down at the water, taking the opportunity to check his back. Nobody there. No barges, no people. Nobody waiting in the bushes to sneak up on him. Too cold for anglers and canoeists, and walking on water was a skill not seen anywhere in nearly two thousand years.

Nicole stood up as he approached, smoothing down her coat with a quick, nervous movement of her hands.

‘I’m sorry for being so mysterious,’ she said, and held out her hand. It felt ice-cold and her face looked blue beneath her dusky skin. She smiled tightly, but he sensed it was to prevent her teeth chattering. ‘I couldn’t be sure who to trust.’

‘This isn’t the best place for a chat,’ he suggested. ‘It will only get colder.’

She nodded and looked behind her, no doubt the way she had come. ‘I know. But there’s something I want you to see. Do you have time?’

‘Sure. How about a hint. Are you in trouble?’ He didn’t want to lead her, but neither did he feel like waiting too long for her to say what had brought her here. The one thing he was certain of was that it wasn’t in response to his rugged good looks or his sartorial tastes.