Joe fidgeted with his blotter and launched into his account. Always give the good news first. He tried for a positive tone, picking out the first favourable aspect of this whole murky affair that came to mind. ‘Well, it seems that Hopkirk and I had it right all along. A common domestic murder, not an assassination, is what we had to deal with. And what has triumphed in the end is – as you noted – good old regular police work. The superintendent has done some ferreting around in Sussex and reported back to me. He’s banged on doors and interviewed bank managers in the time-honoured way.’

He pulled a page of notes from under the telephone and glanced at them briefly. ‘Frog’s Green, that’s the village. Sebastian Marland’s motor business is not as healthy as we had been led to believe … managers sacked, disappointing trials … though banking records reveal no evidence that he is actually in debt yet. And he has an alibi for the night of the killing, if not a watertight one. His housekeeper, who appears devoted to the chap, declares he went to bed early and was still abed when she took him his early morning cup of tea. She’s the kind of lady whose evidence would stand up wonderfully in court … you can imagine?’

‘No mention of a phone call in the night?’

Joe smiled at her perception. ‘No. She reports that, after a hasty breakfast, the young master made two phone calls and screeched off in his car, claiming he was responding to an emergency.’

‘But didn’t Cassandra imply that she’d spoken to him in Sussex straight after the murder? I’m sure she told us she had.’

‘It was vaguely phrased to lead us astray. I don’t believe Cassandra has any idea that records of trunk calls are available to us. I checked. Many calls were made from her telephone that night, but none to Sussex. I don’t think we could make an accusation stick. He could certainly have sneaked off up to London. He could have loitered in evening dress in Melton Square or anywhere in Mayfair and not raised an eyebrow. He certainly wouldn’t have been bothered by the beat bobbies. As you say, upper-class drunks are ten a penny on a Saturday night. And, as the cabby observed, steady gun hand, unsteady on his pins. He could have done it. Hired the Irishmen and hung around to make sure they did the job. But we run into another factor that would get me a clip round the ear if I approached the Director of Public Prosecutions with a request for arraignment. There’s no kind of motive – financial, I mean – that would stand up and convince. He inherits a modest lump sum from his uncle and a yearly retainer for supervising the boys, and he had foreknowledge of that, but it’s a long way short of a fortune. No judge in the land would accept it as an incitement to murder.’

‘But if he were to marry Cassandra, sir?’

‘Ah. Then we have a different scenario entirely. The widow has money of her own and a good slice of the admiral’s wealth comes to her too. But it would be assuming quite a lot, wouldn’t you say?’

‘Yes. And to take the risk, he’d have had to be able to count on gaining her affection?’

‘Exactly. Quite a gamble.’

Lily frowned and took a deep breath. ‘What I’m thinking is – there was no gamble. He already had it, sir. Her affection, I mean.’

‘Explain yourself, Wentworth.’

‘I didn’t have the impression that he was the kind of man who would kill a close family member for an uncertain source of cash. We know that he’s a man hardened and made ruthless by his wartime experience – he’s used to shooting people, to put it bluntly. But I think it would take a much stronger reason than financial gain to make the man I saw this afternoon pull a trigger in cold blood.’

‘What have you in mind?’

‘The strongest motive of all. Love, sir. For Cassandra, yes. But more than that. He has affection for those boys too. Neglected by their father, they must have felt he filled a certain gap in their lives. They clearly love and trust him. An older man, a war hero but not one on a pedestal. A man who looks them in the eye and understands their needs in a way their father was not able to do. Didn’t you get a feeling of … unity … common purpose … understanding which we weren’t invited to share in when we were there this afternoon, sir?’

Joe nodded. ‘I was happy to see the family closing ranks. Quite proper.’

‘The admiral was on the point of retiring, wasn’t he? The whole family must have had mixed feelings about that. His return to the family hearth after years away striding the bridge might not have been entirely welcome in some quarters. Autocratic, authoritarian and no longer five hundred sea miles distant …’

Joe grunted. ‘Silly, bone-headed old twit. Dedham, I mean. It was young William who precipitated the whole thing, I shouldn’t wonder. The first time he ran away from school his father, who was at sea, had him sent back – by telegraph. Last winter he ran off again, apparently. This second time the admiral happened to be at home. He gave him a talk about disgracing the family by behaving like a weed, administered a good thrashing and sent him straight back to school, where he was thrashed again. Cassandra was distraught and, I think, angry.’

‘You’re never going to say it, sir, so I will: it’s a conspiracy we’re looking at, isn’t it? Penelope got tired of waiting for Odysseus. She got fed up with unpicking that wretched weaving of hers and fell for one of the suitors.’

Joe sighed and spoke reluctantly. ‘It was Sebastian who pulled the trigger but it was with Cassandra’s knowledge and perhaps more … she might have devised the whole scheme. Under the layers of scented chiffon, she’s as tough as old boots, I’d say. And I’d guess, Wentworth, they’ve been lovers for quite some time. They have that trick of reading each other’s mind – finishing sentences, speaking for each other – did you notice? And on a practical note – Cassandra knew in advance exactly where the admiral would be and when on that evening.’

‘So her affectionate attentions to you were nothing more than a blind. If she’s embarrassing you with suggestions of interest …’

‘Say rather intriguing, Wentworth. I was not embarrassed.’

‘Very well, sir. Drawing you in, luring you with kisses and cake … you’re not going to suspect her of an amorous connection with anyone else, are you?’

‘I didn’t. Not at all sure I do now,’ he added rebelliously.

Lily noticed his gathering unease and changed tack. ‘And then there’s her shooting. She tells me you taught her and that she was a very poor pupil? You despaired of her ever hitting a target?’

Joe looked up sharply and frowned. ‘That’s not right, no. As a matter of fact, she was rather good. I’ve known one or two women who were adept with firearms.’ He smiled briefly. ‘I owe my life to their skill and readiness to use them. Cassandra fussed and pretended to be hopeless but she could hit a target all right. Well she did, didn’t she? She was pleased and surprised.’

‘Exactly. And if she’d hit and killed both Irishmen she’d have been even happier. It was probably always her intent to eliminate them. Just in case. It was pure bad luck for her and Sebastian when Mrs Colonel Belton hove into view and commandeered the getaway taxi. She rather fouled things up.’

Joe had no time for protective self-deception. ‘We were taken in, Wentworth. By a skilled actress.’ This was the moment to rip off the bandage and assess the damage underneath. ‘You were rather less taken in than I, I have to say.’

‘Oh, I swallowed it whole – the flattery and the flannel. Faithful Penelope! Ha! The tears, the confidences, the “brave little widow” stuff. And all the time she was using me as an unsuspecting source of inside information on the inquiry.’

‘Inside information? What did she wring out of you? You’d better tell me.’

‘I’m afraid I confirmed the existence of the third shooter, sir.’