Dalgliesh said, “If we assume that neither Chandler-Powell nor Bostock was lying—and I don’t think Bostock was—then someone in the house unbolted that door after eleven o’clock, either to leave the Manor or to let someone in. Or, of course, both. That leads us to Mogworthy’s alleged sighting of a car parked near the stones shortly before midnight. Miss Gradwyn was killed either by someone who was already in the Manor that night—a member of staff or someone else who had gained access—or by someone from outside. And even if that person had the two security keys, he or she couldn’t gain access until the door was unbolted. But we can’t go on talking about ‘he or she.’ The murderer needs a name.”

The murderer was always given a name by the team, since Dalgliesh strongly disliked the usual soubriquets, and usually it was Benton who supplied it. Now he said, “We usually make it a he, sir, so why not a woman for a change? Or an androgynous name which would do for either sex. The murderer came by night. How about Noctis—by or from the night?”

Dalgliesh said, “That seems appropriate. Noctis it is, but let’s keep him male for the present.”

Kate said, “We’re still back with the problem of motive. We know that Candace Westhall tried to persuade Chandler-Powell not to let Rhoda Gradwyn come to the Manor. If Westhall had murder in mind, why discourage Chandler-Powell from admitting her? Unless, of course, it was a double bluff. And isn’t it possible that this was an unpremeditated death, that Noctis hadn’t got murder in mind when he went to that room?”

Dalgliesh said, “Against that, of course, is the use of gloves and their destruction afterwards.”

Benton said, “But if it was premeditated, why now? With only one other patient, and all the non-resident staff absent, the circle of suspects is bound to be smaller.”