‘True,’ she agreed, ‘but would you buy it?’

‘I don’t even like going in it,’ he whispered to her conspiratorially. ‘Gives me the willies. What’ve you got for me?’

Dr Harris leaned down and drew a dossier from her briefcase. Placing it on the table she took a handful of nuts, leaned back and looked out the window again, sipping her drink between salty mouthfuls.

Gamache put on his half-moon reading glasses and spent the next ten minutes going over the report, finally putting it down and taking a contemplative sip of Dubonnet.

‘Niacin,’ he said.

‘Niacin,’ she agreed.

‘Tell me about it.’

‘Besides the niacin she was a healthy, though perhaps underweight, forty-eight-year-old woman. She’d given birth. She was pre-menopausal. All very natural and normal. Her feet were charred from the shock and her hands were blistered, in the same pattern as the tubing of the chair. There was a tiny cut underneath that but it was old and healing. It’s all consistent with electrocution except for one thing. The niacin.’

Gamache leaned forward, taking his glasses from his face and tapping them gently on the manila folder. ‘What is it?’

‘A vitamin. One of the B complex.’ She leaned forward so that they were both talking over the table. ‘It’s prescribed for high cholesterol and some people take it thinking it can increase brain power.’

‘Can it?’

‘No evidence.’

‘Then why do they think that?’

‘Well, what it does produce is a facial flush, and I guess someone thought that meant blood was rushing to the brain and you know what that can only mean.’

‘More brain power.’

‘Isn’t it obvious?’ She shook her head in disdain. ‘Fitting that people with so little brain power would come to that conclusion. A normal dose is five milligrams. It’s enough to slightly raise the heart rate and the blood pressure. As I said, it’s often prescribed by doctors, but it’s also available over the counter. I don’t think you can overdose on it. In fact, it’s even put into some breakfast cereals. Niacin and thiamin.’

‘So if the normal dose is five, what did CC have in her?’

‘Twenty.’

‘Phew. That’s a lot of cereal.’

‘Captain Crunch a suspect?’

Gamache laughed, the wrinkles round his eyes falling into familiar folds.

‘What would twenty milligrams have done to her?’ he asked.

‘Produced quite a flush. A classic hot flash. Sweating, discoloration of her face.’ Dr Harris thought some more. ‘I’m not all that familiar with it so I looked it up in the pharmacopoeia guide. There’s nothing dangerous about niacin. Uncomfortable, yes, but not dangerous. If the person was hoping to kill her, he got it wrong.’

‘No, I think he got it just right. He did kill her, and niacin was an accomplice. CC de Poitiers was electrocuted, right?’

Dr Harris nodded.

‘And you more than anyone knows how hard that is.’

Again she nodded.