Valdarno was business-like and succinct. An ambulance and a doctor were sent for, the doctor being, as far as Alleyn could make out, the equivalent of a Home Office pathologist. The guard at all points of departure from Rome was to be instantly stepped up. Toni’s premises were to be searched and the staff examined. Mailer’s apartment was to be occupied in such a way that if he returned he would walk into a trap. Violetta’s known associates were to be closely questioned.

Alleyn listened, approved and said nothing.

Having set up this operational scheme, the Questore turned his deceptively languishing gaze upon Alleyn.

‘Ecco!’ he said. ‘Forgive me, my friend, if I have been precipitate. This was routine. Now we collaborate and you shall tell me how we proceed.’

‘Far be it from me,’ Alleyn rejoined in the nearest Italian equivalent to this idiom that he could at the moment concoct, ‘to do anything of the sort. May we continue in English?’

‘Of course,’ cried the Questore in that language.

‘I suppose,’ Alleyn said, ‘that now you have so efficiently set up the appropriate action we should return to the persons who were nearest to the crime at the time it was committed.’

‘Of course. I was about to say so. And so,’ Valdarno archly pointed out, ‘you interview yourself, isn’t it?’

‘Among others. Or perhaps I may put myself in your hands. How would you set about me, Signor Questore?’

Valdarno joined his fingertips and laid them across his mouth. ‘In the first place,’ he said, ‘it is important to ascertain the movements of this Mailer. I would ask that as far as possible you trace them. When you last saw him, for example.’

‘The classic question. When the party was near the iron stairway on the middle level. We were about to go down to the Mithraic household on the lowest level when Lady Braceley said she was nervous and wanted to return to the top. She asked for her nephew to take her up but we found that he was not with us. Mailer said he had returned to photograph the statue of Apollo and that he would fetch him. Lady Braceley wouldn’t wait and in the upshot Major Sweet took her up to the basilica garden—the atrium—and rejoined us later. When they left us Mailer set off along the passage, ostensibly to retrieve Kenneth Dorne. The rest of us—the Van der Veghels, Miss Jason and I, with Barnaby Grant as guide, went down the iron stair to the Mithraeum. We had been there perhaps eight minutes when Major Sweet made himself known—I put it like that because at this point he spoke. He may have actually returned un-noticed before he spoke. The place is full of shadows. It was some five or six minutes later that Kenneth Dorne appeared, asking for his aunt.’

‘So Mailer had not met this Dorne after all?’