Cullercoats was on the coast south from Mardle, a pretty cove between the wide sweeps of beach at Tynemouth and Whitley Bay. On the front a couple of restaurants and a wine bar looked out to the sea. In the summer it was a place for eating and drinking at tables on the pavement, watching the kids play on the beach. Holly had spent happy evenings in the village with friends. Now, as the light was fading and cold rain blew in from the sea, it was grey and dismal. She parked in a side street and crossed the main road that followed the coast. A light marked the end of the pier. The occasional car splashed through the icy puddles, but nobody else was out.

The laboratory was a red-brick villa with a modern extension, built almost on the beach. Inside, the students were calling it a day, pulling on outdoor clothes and packing equipment into bags. Craggs was a gentle Lancastrian in his sixties. Holly thought he looked too old and heavy to be clambering around in small boats. She found the group in a small room kitted out with lab benches and metal stools and he stood at the front, calling goodbye to the young people, wishing them a happy Christmas. Holly felt a pang of regret. She’d been a graduate entrant into the police service. She’d enjoyed her time at university. Perhaps, after all, she’d have been better suited to life as an academic. Then reality kicked in: Nah, you’d have been bored rigid.

He looked up and saw her. ‘Hello! Anything I can do?’ He was friendly and sounded genuinely helpful. But Holly seldom found older men unfriendly. They were flattered by the attention of a young, attractive woman, even when they discovered what she did for a living. Now the room was clear of students and she identified herself.

‘What’s this about?’ No anxiety. He turned to glance at a row of test tubes behind him.

‘You haven’t heard about Margaret Krukowski?’ But perhaps, after all, it wasn’t so hard to believe. The students wouldn’t be interested in the death of a woman who would appear to them impossibly old. They’d be gearing up for the end of term – this was obviously their last seminar before leaving for the Christmas holidays – and the main preoccupation for everyone seemed to be the weather. And even now Craggs seemed focused on his research. He moved his attention to the microscope on the table in front of him as if he longed to get back to it. He frowned. ‘Kate Dewar’s Margaret? No. What’s happened?’

‘She was murdered,’ Holly said. ‘Yesterday afternoon. Stabbed while she was in the Metro on her way home.’