Somebody must have seen the murderer entering or leaving the hotel. He wasn’t a phantom. The problem was that nobody who’d seen him would know they had been looking at a killer. After all, he wouldn’t have been cackling and carrying a knife dripping with blood. That was the thing about murderers: they usually look just like everyone else.

Heidi Shillingham, the hotel manager, was waiting for them in the same conference room where they’d interviewed the cleaner a couple of days before. Heidi had grey smudges under her eyes and Lennon noticed her bite down on a yawn as she greeted them.

‘Ms Shillingham,’ he said.

‘Oh, call me Miss, please,’ she replied with a tired smile. ‘I can’t be doing with any of that feminist nonsense. In fact, call me Heidi.’

Carmella raised an eyebrow.

Patrick said, ‘We want to talk to you about room 365. Specifically, how the perpetrator and the victim got inside. We don’t know which one of them entered the room first, or if they arrived together. But we need to know how they got in.’

Heidi nodded. ‘OK. Well, all of our rooms are controlled with these key cards.’ She produced a white credit-card-sized key, the type Patrick had seen and used many times before. ‘It’s pretty standard. The magnetic strip on the back controls which room you can access. When a guest checks in, we give them a key card and set it to their room using the central computer system.’

‘I understand all that. What if someone kept their key after they checked out? Could they come back the next day, or a week later, and use it again?’

As Patrick predicted, Heidi shook her head. ‘No. The card – or, rather, the link between the card and the room – is cancelled when the guest checks out. Then the next time the card is used, it will almost certainly be set to a different room.’

‘Had anyone reported losing a key on the day in question?’ Carmella asked.

‘Yes, I checked this. One person. But that was room 218. The system clearly shows that no cards were set to room 365 last Wednesday.’

‘What about master keys?’ Patrick asked. ‘Staff always seem to be able to get into any room. Like the cleaners. I guess they have a master key to all the rooms?’

‘Only for the rooms they are cleaning.’

‘So only Mosope Adeyemi had a key for room 365 that day?’

‘Yes. And the day before too. The day of the . . . unfortunate incident.’

That’s one way of putting it, Patrick thought. ‘And what about you, Ms – Miss – Shillingham, er, Heidi?’ He was gratified to see Carmella’s lips twitch at the same time that Heidi pursed hers. ‘Do you have a master key to all the rooms?’

She hesitated. ‘Yes, I do. Several of the staff have them. But they are on our person all the time we’re in the hotel, and they’re deactivated when we go off shift.’

Patrick drummed his fingers on the table. ‘Have you ever had any issues with people accessing rooms that they shouldn’t? Any thefts? Guests going into the wrong room?’

Heidi squirmed in her seat. ‘No . . . Well, sometimes staff accidentally allocate a room twice, so we’ve had incidents of guests walking into a room that’s already occupied. Which can be highly embarrassing.’

‘I can imagine.’

‘And there was one incident . . . But not at this hotel.’ The way her eyes jumped around the room made it clear that Heidi was worried about getting into trouble.

‘Go on.’

‘A couple of years ago, someone got into a few rooms at one of the hotels in Essex and stole valuables – a laptop, an iPad, some jewellery, cash. It turned out that they had – how did they put it? – reverse-engineered a master key so it was able to open any door.’

‘Hang on – you mean they basically created their own master key, waltzed into the hotel and opened whatever door they fancied?’

‘That’s how I understood it. It was this young lad, a hacker. But he got caught after boasting about it on his website. Stupid prat. I know we made some changes to the security system after that and we were all told it wouldn’t happen again. But . . .’

‘But?’

‘Well, you know what these hackers are like. It’s a challenge, isn’t it? Maybe that’s what happened here.’

Patrick and Carmella took the lift back to the third floor. Patrick wanted to see the room again, not because he expected to find any useful information there but because being at the scene of the crime helped him focus, allowed him to imagine the scene. He used the key Heidi had given them to open the door, which was still sealed off with yellow tape.

‘So our murderer is also a hacker who knows how to reverse-engineer hotel keys?’ Carmella said.

Patrick sighed. ‘It seems unlikely, doesn’t it? Let’s talk to the tech guys, but I’m guessing it isn’t easy to do.’

‘But maybe our murderer acquired a hacked key from someone. Bought it online, or paid someone to create one.’

‘That’s exactly what I was thinking.’ He tapped the key against the palm of his hand. ‘Which means we might finally have a lead.’

Patrick ducked under the tape and entered the room, Carmella following. The smell of perfume had faded now and been replaced with the musty smell of closed rooms and dust. The Travel Inn had asked the police not to release the room number to the press, fearful that no-one would ever want to stay here again. Patrick wanted to tell them not to worry. There were probably a lot of people out there who would get a kick out of staying in a room where a girl was murdered.

The perfume that had been sprayed into Rose’s wounds was being analysed at the lab and results were expected back soon. Patrick didn’t expect to learn much from this. What difference would it make if the killer used Chanel No.5 or CK1? Maybe it would tell them whether he could afford expensive perfume, but that was about it. All the wheelie bins and patches of wasteland within a mile radius had been searched, but there was no sign of Rose’s clothes. They were probably on a dump somewhere, Patrick thought.

‘Let’s get back to the station,’ he said. ‘We need to find out if there are any hackers for hire out there selling hotel key cards.’

As they left the hotel, his mobile rang. It was Gareth.

‘Ah, Gareth, I’ve got a job for—’

Gareth interrupted. ‘Sorry, boss, but something’s happened.’

Patrick stopped walking and gestured for Carmella to wait. The rain pummelled the pavement, soaking the two detectives as Patrick bent almost double, protecting his phone from the downpour. He couldn’t hear what Gareth was saying.

‘Can you repeat that?’

‘I said, we’ve found another body. Another girl.’

Chapter 11

Day 3 – Chloe

Chloe Hedges sat on the edge of her bed and checked her phone for the twentieth time in the space of five minutes. She had been caught on the horns of this particular dilemma for the last few hours – Jess had not returned her calls or texts since they’d parted after last night’s vigil. This in itself wasn’t unusual – Jess was the touchiest of all Chloe’s friends and could be offended at the drop of a hat, leading to a period of cold-shouldering for perhaps three or four days. And they had argued after the vigil – Chloe had got annoyed with Jess’s bizarre and irreverent behaviour. After the singing ended, Jess had got the giggles during the two minutes’ silence for Rose, when Chloe had suddenly found that tears were pouring down her own face, even though she hadn’t known Rose in real life. It was the sight of Rose’s poor parents that had set her off. She imagined it was her who’d been brutally murdered, and that it was her mum and dad up there at the front of the small gathering, looking as though their lives were over too. Already annoyed because Jess wouldn’t tell her why she was acting so weird, she’d snapped at her friend, who had then stormed off, leaving Chloe to get the bus home in tears on her own.