"Ah well -" Taverner sighed. "It's all theory and conjecture! I managed to scare him all right, but that doesn't prove anything. He's just as likely to be scared if he's innocent. And anyway, I rather doubt if he was the one actually to do it. More likely to have been the woman - only why on earth didn't she throw away the insulin bottle, or rinse it out?" He turned to the Sergeant. "No evidence from the servants about any goings on?"

"The parlourmaid says they're sweet on each other."

"What grounds?"

"The way he looks at her when she pours out his coffee."

"Fat lot of good that would be in a court of law! Definitely no carryings on?"

"Not that anybody's seen."

"I bet they would have seen, too, if there had been anything to see. You know I'm beginning to believe there really is nothing between them." He looked at me. "Go back and talk to her. I'd like your impression of her."

I went half reluctantly, yet I was interested.