‘I really don’t think so. It’s possible, I suppose, that she could have phoned the unit where she was treated as an in-patient. I’ll check. If they’ve heard from her I’ll get back to you.’ She paused again. ‘You will be discreet, won’t you, inspector?’

In the hotel he talked to Billy Watt, one of the regular workers on the ferry that ran from Whalsay to Shetland mainland. By now the bar was closed. Berglund had taken himself to bed without waiting to hear if there was news of Hattie and Billy had come along as a favour. He couldn’t get there earlier because his son wouldn’t settle. ‘He’s teething,’ Billy said, a great grin on his face. ‘Poor little man.’ They sat in Perez’s room, drinking coffee.

‘I think she might have left Whalsay on an afternoon ferry. Have you seen her about? Little, very dark. Would you recognize her if she went out with you?’

‘I don’t know her, but we don’t take that many foot passengers. I’d remember if she came out while I was working. There was no one like that on my shift.’

‘What time did you start?’

‘Four o’clock this afternoon. There were two ferries working today like there usually are. Just because I didn’t see her doesn’t mean she didn’t leave the island.’

Perez was wondering what could have scared the girl so much that she’d run away. I should have persuaded her to talk to me on the phone, he thought. I should have dropped everything and come to Whalsay immediately. She had three hours to wait between leaving Paul Berglund and seeing me. What happened that she couldn’t bear to wait three hours?

‘I’ll talk to the rest of the crew,’ Billy said. He sat on the windowsill of Perez’s room at the front of the hotel and looked out to the trawlers moored in the harbour. Further out to sea a buoy was flashing. ‘Will it wait till the morning now? I wouldn’t want to bother them if it’s not desperate. Some of them are working the early shift tomorrow.’

She’s an adult, Perez thought. Twenty-three. An intelligent young woman. ‘No,’ he said. ‘It’ll wait until the morning.’

He expected Billy to make an excuse and leave, but the man sat there drinking the last of the instant coffee made using the kettle in the room. When Perez offered him another one he accepted. Perez was glad of the company. At least with Billy here he could keep Hattie’s disappearance in some sort of perspective. When the crewman left, his imagination would run wild.