‘That would be Dr Tony Hill?’ Petra wasn’t giving up.

Carol massaged her forehead with thumb and forefinger, shielding her eyes with the rest of her hand. ‘That would be Tony Hill, yes,’ she said, sounding exasperated. She dropped her hand and gave Petra a cold, defiant stare. It was as if she was challenging the other woman to make something of it.

Petra could sense that her mention of Tony’s name had stirred something deep inside Carol, but she had no way of telling whether that was positive or negative. ‘I’m sorry, Carol. I don’t mean to offend you by asking you about these cases. I realize they must have been tough to work. I really don’t mean to bring back bad memories. But if I can explain …?’

Carol shrugged. She was going to have to work with Petra on the toughest assignment of her career. Already, she liked and respected her and she knew she needed that to continue. It wouldn’t hurt to hear what she had to say. ‘I’m listening,’ she said as the waitress arrived with her second drink. ‘You might want another drink?’

Petra shook her head. ‘Later. OK. First thing is, I’m a dyke.’

Carol had wondered, but it wasn’t a big enough deal for her to have wondered much. ‘Makes no difference to me.’

‘I didn’t think it would, but that’s not why I’m telling you. I’m trying to explain how this all started. I hang out on a private website for gay and lesbian cops in the EU, and that’s where I met Marijke. She’s a brigadier in the Dutch police, based in Leiden. We talk three or four times a week in a private chat room, and we’ve got close over a period of time.’ Petra’s smile was crooked, self-mocking. ‘Yes, I know what they say about meeting people over the net, but it’s clear that she is who she says she is, not some impostor fishing for information or a cop junkie who gets off on pretending to be one of us. So, me and Marijke, we each found in the other the sounding board we lacked in our everyday lives.’

‘Doesn’t make you a sad bastard,’ Carol said with a smile of reassurance.

‘No. Anyway, Marijke and I have the habit of being confidential with each other. Just over a week ago, she had a murder in Leiden. She told me about it because it was such a strange case, with no obvious suspect or line of inquiry. The dead man, Pieter de Groot, was a professor of psychology at the university there. He was found naked, tied across the top of his desk. The killer had forced some sort of tube into his throat and poured water down it until he drowned.’

Carol shivered. ‘That’s seriously nasty.’