“He was in the process of extorting money to keep a secret. I didn’t hear his victim’s voice clearly, just Haworth’s half of the conversation, but it was a man. And if someone in this house was being blackmailed—”

“Now hold on a blasted minute,” Bill said furiously. “Nobody is blackmailing me, and you cannot possibly think I had anything to do with Haworth’s death!”

“You lied about Jimmy’s whereabouts. He said you weren’t together and you stopped him and gave him an alibi. Jimmy had as good reason as anyone in the world to hate Haworth, and you were both in the East Wing when he was killed. And—and I don’t care about that ghastly man, he had it coming, but I want to know exactly what the devil you’re playing at because he’s dead and you two lied!”

Jimmy was a horrible shade of grey. Bill looked as if he might be sick. “You’re wrong. Neither of us laid a hand on Haworth. We were together all that time—” Pat made a strangled noise. “We were,” Bill insisted. “For God’s sake, Pat, I didn’t lie. Jimmy did.”

“Jimmy? Jimmy made up a lie so as to not have an alibi?” Her voice was rising to the kind of pitch Fen could achieve. “How stupid do you think I am? You lie in murder investigations to look less guilty, not more!”

“Oh Christ.” Jimmy turned away, shoulders hunched, a picture of wretched shame.

Bill shot a glance at the locked door and lowered his voice to a subdued snarl. “He was trying to make us look less guilty, curse it. There are other offences as well as murder, and some of them prey on the mind!”

“What other—”

“Pat,” Fen said, voice warning. “Deep breath, and think.”

Pat thought. Then she sat down, heavily, and put her face in her hands. After a moment of silence there was a rustle, and Fen’s fingers closed on her shoulder.

“Pat.” Bill sounded anguished. “You aren’t crying, are you? I dare say you’re upset, but—”

“I’m not crying and I’m not upset, you fool,” Pat said, smacking away a tear. “I’m relieved. Do you have any idea what that looked like, telling Jimmy where he was and what to say, with him having so much reason to loathe the ghastly man?”

“I’m sorry, old thing. You must see, I had to shut him up before he talked himself onto the gallows. ‘Oh no, I was definitely on my own all that time.’ Idiot.”

“I’m sorry,” Jimmy said, muffled. “I didn’t think.”

“You never do,” Bill said. “You never bloody do.”