that I still can't explain, like removing my watch without my being aware of it and having it turn up inside a box of chocolates. This business with the stamp is just as miraculous. I can only account for it as a brilliant conjuring trick. I can't guess the solution.'
'And the murder of Sid Towers-is that magic?'
'The circumstances are.'
'Trickery.'
'Magic or trickery, it's beyond my understanding.'
'That's a conclusion I'm not permitted to make,' said Diamond. 'I've got to catch the conjurer. Do you have any suspicions?'
'Of whom?'
'The other Bloodhounds.'
'How can I?' said Milo. 'They're charming people, all of them. Oh, Miss Chilmark has the reputation of being a sourpuss, but she's all right when you take a little trouble with her, butter her up, you know. And Jessica Shaw went out of her way to help poor old Sid fit in. She took him for a drink on more than one occasion. No, I'm afraid if you're looking for suspects, they're a very unlikely bunch. Not like a detective story at all. In this case, I can't think of anyone with a grudge against poor old Sid.'
Chapter Eighteen
Later the same afternoon, Diamond drove Milo Motion to the Dundas boatyard to collect his change of clothes from the Mrs. Hudson. A thick-knit sweater was likely to be among them, because now that the sun was disappearing behind the willows on the far bank, there was an unmistakable threat of frost in that cloudless sky. The Scenes of Crime team had finished work and left. The only police activity-apart from one luckless constable rubbing his hands to keep his circulation going-was a pair of divers searching the canal bottom for the murder weapon, and they didn't seem too happy either. What they were doing in the shallow water couldn't be described as diving, more a matter of wading about and bending double. On a blue tarpaulin on the towpath they had assembled their finds-a horseshoe, two plastic milk crates, a bicycle pump, a birdcage, about twenty beer cans, and several pieces of stone-the result of three hours' scavenging for fifty yards either side of the narrowboat. Diamond told them to give up for the day. The chance was slim that a killer so artful as this would have disposed of the weapon in so obvious a place, but procedure had required the search to be made. He asked Milo to check for any object missing from the boat that might have been used to crack Sid Towers over the head.
Milo said he was unable to think of anything, but he would certainly look.
The constable had to open up for them, because the door at the stern had been fitted with a fresh lock. Milo's German-made padlock had been stripped down and examined at the forensic lab. Pressed by Diamond for their findings, the scientists had reported no flaw in the mechanism. No sign, even, of tampering. It was described as a high-security close-shackle padlock. The locking mechanism provided over six million key variations, bearing out the manufacturers' claim that each padlock they sold in Britain had a unique key pattern.
Diamond had been over the narrowboat and its security arrangements many times in his mind without deducing how the body had been placed there, so this extra inspection wasn't embarked upon with much confidence. The murder of Sid Towers was becoming his own locked room mystery, his Gordian knot. If Milo Motion had spoken the truth, the facts were indisputable:
1. Milo locked the boat when he left it.
2. The key never left his person.
3. The keys fitted that padlock and no other. There was no second key.
4. The only other point of entry to the cabin was the door at the fore end, and this was bolted from the inside.
5. The padlock was still in position when Milo returned to the boat with Wigfull. He had opened it with the key and discovered the corpse of Sid Towers in the cabin.
Each time he looked for a flaw in the logic, Diamond was forced back to that qualifier: if Motion had spoken the truth. The hardware, surely, was foolproof; the human assurances had to be tested further.
The two men dipped their heads to enter the cabin, now stripped of its carpet.
'I want you to think hard and long,' Diamond told Milo. 'Do you keep anything in here that might have been used as a weapon? Some ornament, perhaps, like a heavy beer mug or a paperweight?'
Milo thought for a moment and shook his head. 'Books are about the heaviest things in here. You couldn't kill someone with a book, could you?'
'It would take something heavier than those,' Diamond admitted, eyeing the shelves of detective stories. 'A really big dictionary might do the job.'
'Can't help. I manage without one.'
'Lucky for you. Good speller, are you?' he asked companionably. Putting the man at his ease might encourage him to talk more freely about the evening of the murder.
'Correct spelling was part of the education when I grew up.'
'Mine, too.' Diamond switched to a confiding mode. 'I was at grammar school, but I never fully mastered the spelling. Bit of a handicap, because they deducted marks in every subject, and it all went on a weekly report card. There was a ritual on Saturday mornings called 'slackers' parade'-a painful encounter with the deputy head-and I was a regular on it. Then one of the English masters taught me the trick of avoiding words like necessary. You can always write needful instead. Good advice. So the next time, that's what I did-and still finished up on the slackers' parade. Pity he didn't warn me needful has only one / at the end. Tell me, what's the attraction of detective stories?'
Milo blinked and frowned, derailed by the unexpected admission of frailty by the man he'd come to regard as the embodiment of authority.
'I've never understood what people see in them,' Diamond went on. 'True crime, yes, I can read with pleasure. Fiction I can't.'
'I suppose it's the not knowing.'
'The what?'
'The not knowing… until the end,' Milo explained.
'Not knowing who did it?'
Milo relaxed slightly. 'That's true of some books, certainly, but not all. There are other things the reader is keen to discover these days. I mean, some books tell you right off who the villain is. There's the fascination of not knowing whether he gets away with the crime, or whether the good chap survives. There's much more emphasis on character these days, but there's always an element of surprise in the best mysteries. You should attend one of our Bloodhound meetings.'
'I may end up doing that. Would you mind stepping into the kitchen, or the galley, or whatever you call it?'
'You'd like a coffee?' said Milo.
'No, Mr. Motion.' Abruptly he was the investigator again. 'We're checking for a possible murder weapon. Remember?'
'Ah.'
Nothing was missing from the galley that Milo could recall.
'You appreciate the importance,' Diamond said to take the edge off his sharp remark. 'The choice of weapon can tell us if the murder was planned or was just a response to something unexpected. Did the killer bring a weapon here with murder in mind, or was it just a matter of snatching up the first thing that came to hand?'
'I follow you,' said Milo.
'But you can't help me?'
'On this matter, no.'
'While we're here, let's go over the business of the padlock,' Diamond continued. 'I know you've been through it so many times you could say it in your sleep, but something else needs to be explained, doesn't it? The boat was totally secure, according to you, and yet a murder took place in here.'
