Both lanistae had produced impeccable alibis, Calliopus proving he was at the theater with his mistress (in his wife Artemisia's absence at the Surrentum holiday home) and Saturninus declaring he had been out to dinner with Euphrasia, which cleared her too. Very gallant. And meticulously convenient-as I had learned to expect.

Alibis were immaterial. Both men owned groups of trained killers. Both knew plenty of murderous types outside their own exercise yards who could be coerced into bad deeds. Both could wield seriously persuasive quantities of cash.

There was one particular suspect to check up on: Calliopus' allegedly rogue bestiarius, Iddibal. I went to interview him. I was told he had been bought out by a rich aunt, and had left Rome.

Now that did smell suspicious. I had seen the supposed "aunt" with him, so I knew she existed. But as a gladiator, Iddibal was a slave. Apparently he had originally been a free volunteer, but his status had changed when he enlisted. When he signed up, he had sworn the oath of complete submission: to the whip, the branding iron, and death. There was no backing out. No lanista would ever let his men hope for escape. Gladiators were held to their gory trade by the knowledge that their only route to freedom was through death: their own, or those of the men and animals they vanquished for the pleasure of the crowd. Once in, only many victories could bring escape; being bought out was never a possibility.

Anacrites was with me when I put this to Calliopus. We told him he was liable to be drummed out of the guild of lanistae for allowing the unthinkable. He squirmed and said the woman had been very persistent, her offer had been financially attractive, and anyway Iddibal had been regarded as a troublemaker, moody and unpopular, ever since he joined. Calliopus even claimed Iddibal had had a wall-eye.

It was nonsense. Early in our investigation, I remembered seeing Iddibal throwing spears among his colleagues with good humor and a very keen aim. I also remembered one of the keepers telling me that when the crocodile who ate another member of staff was put down in the arena it was done by "Iddibal and the others"; that sounded as though in the venatio he had been at least one of the pack, if not actually a leader. Calliopus said no; we thought he was lying. Deadlock again.

We managed to trace Iddibal's movements on the night of the Rumex killing. He had gone, along with the so-called aunt and her servant, all the way to Ostia. We should have caught them there, but the party had actually sailed south in December, a suicidal risk. We could not think how they persuaded a captain to take them at that time of year. The woman who had plucked Iddibal from the barracks must be absolutely loaded. Anacrites solved it: she owned her own ship. More curious still.

We decided Iddibal had run away from a wealthy home, and had now been fetched back by his family. Perhaps his auntie was a real one. He had bunked off from Rome for good, anyway, whether he had in fact gone home to mother, or bunked off with some hot-blooded widow purchasing herself a stud.

"This is sordid," said Anacrites. Trust a spy to be a prude.

One further line remained unexplored: the ex-praetor Urtica. Camillus Verus reckoned that the man had not put in an appearance at the Curia for some time. Even the sensational tales about his love life had died down. Magistrates may retire from politics, but a taste for sleazy behavior tends to last. Pomponius Urtica might just be lying low to let his reputation pick up again-but the mauling theory seemed more likely to be true.

Once again I traveled out to the Pincian, this time determined to gain admittance if I had to wait all day. This time they told me the truth: Pomponius Urtica was at home, but very sick. The porter stated that he had gout. I said he could talk to me between groans, and I somehow managed to force my way in as far as the antechamber to the great man's bedroom.

While the attendant doctor was consulted, I noted large quantities of medical equipment, including a bronze stand in the encouraging shape of a skeleton, which had three branches for cupping vessels. Those could be used for a variety of ailments, not least to create diversionary bleeding above a wound. Numerous rolls of bandage were neatly stored on a shelf. There was a smell of pitch-used for sealing holes in flesh, of course. A box with a sliding lid had compartments with hinged lids which contained several ground-up medicines. I stole a pinch of one powder that had been nearly used up and checked it later with Thalia, an expert in exotic substances. "Opobalsamum, I'd say. From Arabia -costs a packet."

"The patient can afford it. What's opobalsamum used for, Thalia?"

"Wounds, mainly."

"How does it work?"

"Gives you a warm glow thinking that anything that costs so much must do you good."

"An efficacious decoction?"

"Give me essence of thyme. Where is he hurt?"

That I could not tell her, for I never saw the man. His doctor barged out from the bedroom, highly annoyed at me being there. He mentioned an ague, then wouldn't discuss the gout story. Servants were called to escort me from the house in a style that only just stopped short of compensatable assault.

I then tried to see Scilla, the ex-praetor's supposedly wild girlfriend. I always enjoy interrogating a woman with a dirty past; it can pose a challenge in several ways. Scilla was not having it. She lived at the praetor's house-and she stayed indoors. As a female way of life it was suspiciously respectable, though I sounded like a cad when I went home and said so.

Thwarted at every turn, Anacrites and I went back to routine enquiries. That meant asking questions of everyone who was known to have been at the barracks the night Rumex was killed, in the hope that someone would remember seeing something unusual. The vigiles were following up the case in parallel with us, though all their enquiries turned up negative too. Eventually they filed the case in their "No further action" pigeonhole, and not long afterwards, so did we.

Thirty-five

WELL, DON'T BLAME me.

Sometimes there is quite simply nothing to follow up. Life is not a fable, where stock characters seethe with implausible emotions, stock scenes are described in bland language, and every puzzling death is succeeded in regular progression by four clues (one false), three men with crackable alibis, two women with ulterior motives, and a confession which neatly explains every kink in events and which indicts the supposedly least obvious person-a miscreant any alert enquirer could unmask. In real life when an informer runs a case into the ground, he cannot expect a fortuitous knock on the door, bringing just the eyewitness he wants, with confirmation of details that our shrewd hero has already deduced and stored in his phenomenal memory. When enquiries run into the ground it is because the case has gone cold. Ask any member of the vigiles: once that happens you may as well go sheepshearing.

Better still, have a drink in a wine bar. There you may possibly strike up a conversation with a man you haven't seen for twenty years, who will spin you an intriguing yarn about a mystery he hopes you can solve for him.

Don't bother: his wife's dead and buried under the acanthus bed; the tortured wag with the haunted eyes who is cadging the house bilgewater off you in this pitiful manner is the bastard who put her there. I can tell you this without even meeting him. It's just a knack. A knack called experience.

People lie. The good ones do it so niftily that however hard you press them you will never catch them out. That presupposes you can even tell which liars you should be pressing. It's pretty hard, when in the real world everyone is at it.