But the darting beam paused and sharpened its focus. Alleyn stooped and peered at the rail.

“There’s a thread of some material caught here,” he said. “Yes, may we have the lights, please?”

The man went back down the passage, his retreating footfall loud on the stone floor.

The torchlight moved away from the rails, played across the lid of the sarcophagus, caused little carved garlands to leap up in strong relief, found the edge of the lid. Stopped.

“Look here.”

Valdarno used his torch and the other two men came forward with theirs. As they closed in, the pool of light contracted and intensified.

The lid of the sarcophagus was not perfectly closed. Something black protruded and from the protrusion dangled three strands of wool.

“Dio mio!” whispered the Questore.

Alleyn said: “Brother Dominic, we must remove the lid.”

“Do so.”

The two men slid it a little to one side, tilted it, and with a grating noise let it slip down at an angle. The edge of the lid hit the floor with a heavy and resounding thud, like the shutting of a monstrous door.

The torchlight fastened on Violetta’s face.

Her thickened eyes stared sightlessly into theirs. Her tongue was thrust out as if to insult them.

Valdarno’s torch clattered on the stone floor.

The long silence was broken by a voice: uninflected, deep, rapid.

Brother Dominic prayed aloud for the dead.

A consultation was held in the vestibule. The church was shut and the iron grille into the underworld locked, awaiting the arrival of Valdarno’s Squadra Omicidi. It was strange, Alleyn found, to hear the familiar orders being laid on by somebody else in another language.

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 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 unnoticed 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?”

“Apparently not but there is some evidence—”

“Ah! I had forgotten. But on the face of it no one had seen Mailer after he walked down the passage?”

“On the face of it — nobody.”

“We must question these people.”

“I agree with you,” said Alleyn.

For some seconds the Questore fixed his mournful gaze upon Alleyn.

“It must be done with tact,” he said. “They are persons of some consequence. There could be undesirable developments. All but two,” he added, “are British citizens.”

Alleyn waited.

“In fact,” said Valdarno, “it appears to me, my Superintendent, that there is no longer any cause for you to preserve your anonymity.”

“I haven’t thought that one out but — no, I suppose you’re right.”

One of the Agenti came in.

“The Squadra Omicidi, Signor Questore, the ambulance, Vice-Questore and the doctor.”

“Very well. Bring them.”

When the man had gone Valdarno said: “I have, of course, sent for the officer who would normally conduct this enquiry, Il Vice-Questore Bergarmi. It would not be fitting for me to engage myself in my subordinate’s duties. But in view of extraordinary circumstances and international implications I shall not entirely disassociate myself. Besides,” he added with a totally unexpected flash of candour, “I am enjoying myself prodigiously.”

For Alleyn the confrontation at close quarters with a strangled woman had not triggered off an upsurge of pleasure. However he said something vague about fieldwork as an antidote to the desk. Valdarno developed his theme.

“My suggestion,” he said, “is this and you shall tell me if I am faulty. I propose to invite these people to my office where they will be received with cerimoniale. There will be no hint of compulsion but on the contrary perhaps a glass of wine. I present you in your professional role. I explain a little but not too much. I implore their help and I then push them over to you.”

“Thank you. It will, don’t you feel, be a little difficult to sustain the interview at this level? I mean, on his own admission to me, Kenneth Dorne has been introduced to soft and then to hard drugs by Mailer. And so, after last night, I believe, has Lady Braceley. And I’m perfectly certain Mailer excercised some sort of pull over Barnaby Grant. Nothing short of blackmail, it seems to me, would have induced Grant to take on the role of prime attraction in yesterday’s conducted tour.”

“In which case he, at least, will be glad to help in bringing about the arrest of Mailer.”

“Not if it means publicity of a very damaging kind.”

“But my dear colleague, will you not assure them that the matter at issue is murder and nothing else? Nothing, as you say, personal.”

“I think,” Alleyn said drily, “that they are not so simple as to swallow that one.”

The Questore hitched his shoulders and spread his hands. “They can be assured,” he threw out, “of our discretion.”

Alleyn said: “What’s Mailer’s nationality-has he taken out Italian citizenship?”

“That can be ascertained. You are thinking, of course, of extradition.”

“Am I?” Alleyn muttered absently. “Am I?”

The doctor, the ambulance men, the Questore’s subordinate, Vice-Questore Bergarmi and the Roman version of a homicide squad now arrived with their appropriate gear: cameras, tripods, lamps, cases, a stretcher and a canvas sheet: routine props in the international crime show.