“I know Stella’s doctor doesn’t like her taking tranquilisers,” she said. “ I think she may have become dependent on them when she first came out of hospital. The dangers of dependence weren’t so well documented then. She’s complained to me sometimes that they’re the only things that help. She asked me if there was any equivalent she could buy over the counter. Of course, there isn’t.”

“So Max might have given Mrs. Laidlaw the prescription to help her, because he felt sorry for her?”

“No,” she said sharply. “ He wouldn’t do that. He’s a good doctor. He knows the rules. I can’t imagine why he would prescribe for her unless …” Her voice dropped.

“Unless?” he prompted.

“Unless she had put him under some sort of pressure. Max is weak. In some situations he might be prepared to take the easy way out.”

“And what might Mrs. Laidlaw be using to put pressure on your husband?”

“I don’t know!” she cried, and he realised he had pressed her too far, too quickly. “I just don’t know.”

“Perhaps,” he said gently, more the doctor himself now than the policeman, “perhaps we have come back again to Max’s affair.”

“I don’t know what you mean,” Judy said. “ Stella wasn’t capable of loving anyone. I’ve explained already. She certainly wasn’t capable of writing that letter.”

“But perhaps,” he said more gently, still reassuring her with his voice, telling her that he knew how hard all this was for her, “perhaps she knew who did write it.”

“Blackmail!” Judy said. “You think Stella was blackmailing him about his lover.”

“Is that possible?”

The speed and certainty of her answer surprised him. “Yes,” Judy said. “She’s a bitch. I’d believe anything of her.”

She thought then that he was through, but he stayed on, pouring more tea for himself and for her, so that she knew his questions had not finished and she must brace herself again for another shock, more unpleasantness.

“You know who it is,” she said suddenly, as if the thing would be easier to bear if it were she who took the initiative. “ You know whom he’s been having an affair with.”

“I’ve an idea,” he said. “ I’ve no certainty.”

“Well,” she demanded. “ Tell me!”