They each took a clear evidence bag. They looked skeptical.

‘So, what? We’re meant to levitate this phone out of the shit?’ said one of the lads.

‘We really appreciate your helping out here, lads,’ said Peterson. ‘You’ve joined us at a crucial stage in a very harrowing case involving young girls who have been murdered. Finding this phone is a large piece of our puzzle. Just try not to touch it with bare hands.’

The men’s attitude changed completely. They rapidly put on their helmets, and started checking their lights and radios. When they were ready, they all stood around the manhole as Mike lowered in a probe.

‘We’re checking for poisonous gases,’ he said. ‘It’s not just shit and piss we have to worry about down there. There’s carbonic acid, which miners used to call chokedamp; carburetted hydrogen, which explodes; and sulphurated hydrogen, the product of putrid decomposition . . . You’ve all got your chemical detectors in your suits, lads?’

They all nodded.

‘Jeez, wouldn’t you all rather work in a supermarket?’ asked Moss.

‘This pays much better,’ said the youngest of the lads as he went first and was slowly winched down into the manhole.

They watched as the remaining men were lowered down into the darkness, their lights illuminating the brown grimy interior of the storm drain. Erika looked across at Moss and Peterson as they leaned over. They exchanged tense glances.

‘Like looking for a needle in a haystack,’ said Peterson. Slowly, the torchlight below began to fade and they were left in silence. Mike went into the van to watch their progress.

An hour later there was nothing to report, and they were stamping their feet in the cold. Then a call came through on the police radio. There was an incident at a supermarket in Sydenham. A man had pulled a gun, and shots had been fired.

‘We’re on call today,’ said Moss, looking up at Peterson. ‘We’d better scoot. Marsh said this wasn’t high priority.’

‘You guys go; I can stay here and wait,’ said Erika. Moss and Peterson hurried off and she was left alone, realising again that she had no badge, no authority. She was just a woman hanging around an open sewer. She stepped into the van and asked Mike how they were getting on.

‘Nothing. We’re almost at the point where I don’t want them to go any further. The network branches off in several directions towards central London.’

‘Okay, where does it all end up?’ asked Erika.

‘Sewage treatments plants around London.’

‘So . . .’

‘So the chances of a tiny little phone showing up are slim,’ he said. ‘It’s not like a dog who’s swallowed a diamond ring and you . . .’

‘Yes, I get the message,’ said Erika. She came back out of the van, perched on a tree stump and smoked a cigarette. The church loomed above her in the cold, and a train clattered past in the distance. The men emerged an hour and a half later, caked in mud, exhausted and soaked in sweat. They shook their heads.

‘As I thought, it could be anywhere right now. Out to sea even. The storm drains have been opened twice since the 12th of January, and so much would have flowed through, nothing would stay down there under that amount of water pressure,’ said Mike.

‘Thank you,’ said Erika. ‘We tried.’

‘No. They tried,’ said Mike, pointing at the men. ‘I said to your boss, it was bloody hopeless, a wild goose chase.’

Erika wondered if that was the reason why Marsh had arranged it. As she walked home in the rain, she remained convinced that Andrea’s phone had to be found. She thought of the letter she’d received and the things left in her bed.

She felt like the only person who knew that the police had arrested the wrong man.

40

Three days passed with no word from Moss or Peterson. All Erika’s enthusiasm and positivity drained away, made worse by having nothing to do. On the third day, she was poised to call Edward and face up to visiting Mark’s headstone, when her phone rang in her hand.

‘Boss, you’re not going to believe this,’ said Moss. ‘Andrea’s phone has just shown up.’

‘What? In the sewer?’ asked Erika, gripping the pen.

‘No. A second-hand mobile phone shop in Anerley.’

‘That’s only a few miles away,’ said Erika.

‘Yeah. Crane circulated the IMEI number around local second-hand phone dealers, saying that if a handset with this number came into their shop they were to contact the incident room urgently.’