Bloodhounds

'Don't you think I'd have told you by now if I knew the answer?' Milo said with injured virtue. 'It's utterly beyond my understanding. What is more, they got in twice. Someone must have broken in earlier to put the stamp inside my copy of John Dickson Carr.'

'There's no evidence that anyone broke in.' Diamond was swift to correct him. 'If they had, we might have an explanation. Not one of the doors or windows was interfered with. Nothing was broken.'

'What happened then? They couldn't have had a key. Mine is the only one in existence.'

'That isn't true, is it? There's the spare one you dropped in the canal.'

'If you want to nitpick to that degree, yes.'

'How long ago did you lose it?'

'Last year. I told you.'

'Exactly when, Mr. Motion?'

Milo sighed. 'Toward the end of the summer. It must have been September.'

'Can you recall the circumstances? I daresay it caused you some annoyance.'

'Well, it did. I lost my car keys at the same time.'

'So we're talking about a bunch-on a ring?'

'Yes.'

'Did you try to recover them?'

'It happened after dark,'' Milo explained, tugging at his beard as if the whole episode was painful to recall. 'If you must know, I was the worse for drink. Pretty unusual for me. A night out at the Cross Guns.'

'The pub at Avoncliff?'

'Yes. Do you know it? Gorgeous on a summer evening. I had the boat tied up at one of the moorings just above the pub, that stretch of the canal before the aqueduct. Treated myself to a meal and a few beers, and when I got back-'

'Alone?'

'Yes. I opened up and stumbled a bit pulling open the door. The damned keys slipped out of my hand and over the side. Bloody annoying, but I knew I had spares for all of them, so it could have been worse.'

'Next morning, did you try and get them out?'

He shook his head. 'Hopeless. They would have sunk into the mud.'

'Did you mention this to anyone else?'

'I may have done to the people in the next boat. Can't remember, frankly.'

'What about the Bloodhounds? Would you have mentioned it to them?'

'Certainly not. Why should I? It wasn't an incident I'm proud of.'

'We've got to think of all the angles.'

'All I can say is what I know to be the truth,' Milo stressed in a more defensive tone. 'You can see for yourself that when I'm aboard the boat, it's just about impossible for anyone else to come in here without my knowing. You can hear every step, and there's nowhere to hide. It's all open-plan. Anyway, the cupboards are far too small to hide anyone.'

'What exactly are you driving at?'

'If the murderer found some way of stowing away while I was still here, and remained hidden when I locked up, it' would be possible to unbolt the door at the far end-unbolt it from the inside-and admit the victim.'

Diamond almost snapped his fingers in triumph. Then, as the flaw in the revelation occurred to him, he converted the gesture into scratching his right earlobe. 'But when you and Wigfull entered the boat, it was bolted from the inside at that end and padlocked outside at the other. Unless the killer was still aboard, it couldn't have happened.'

'There you go,' said Milo with an air of resignation. 'I can assure you, there wasn't anyone here except poor old Sid. I'm as confused as anyone by all this.'

'And as you remarked just now, there's nowhere to hide. Everything folds against the walls. The only lockers are outside the cabin, back at the stern end.' Diamond paused, watching Milo. 'The crucial question is whether your memory is reliable when you say you locked the boat.'

'Of course it is!' Milo said petulantly. 'I remember rattling the damned padlock, testing it with my hand to be sure it was secure. And it was. Later, when I returned with your colleague, Mr. Wigfull, I unlocked with my own key and had the shock of my life when I saw what was inside. It's impossible, but it happened. I am at a total loss to account for it. You need Dr. Fell for this.'

'Who's he?'

'Dickson Carr's detective.'

'A detective in a book? Great.'

'Someone of his caliber, at any rate.'

'Thanks for the vote of confidence,' said Diamond. 'Well, I think we need someone smarter than Dr. Fell. I've been through that chapter on the locked room lecture, and it's no help. I ask you. You've studied it yourself. This is a puzzle that defies all Dr. Fell's explanations.'

Milo nodded. 'I have to agree with you.'

'And the locked room is only part of the mystery. What was Sid's reason for coming here?'

'I haven't the foggiest,' Milo answered with a shrug. 'He wasn't in the habit of visiting me. Besides, he knew I wouldn't be here. I told everyone I was going straight to the police station to hand in the Penny Black. Do you think the murderer lured him to his death?'

Diamond didn't want to trade theories any longer. 'Look, why don't you pick out the clothes you need? I'll take a stroll along the towpath and see you in ten minutes.'

He needed more time for reflection. Milo, surely, was a reliable witness. This, after all, was the one member of the Bloodhounds who couldn't have murdered Towers. Yet there was still a doubt. Any lawyer will tell you that witnesses tend to present themselves and their actions in the most favorable light, sometimes obscuring serious flaws in their evidence. Suppose Milo hadn't after all locked the narrowboat before leaving for the meeting. Suppose through carelessness or over-confidence he had left the padlock hanging from the staple still unfastened. At first he may have decided not to mention it; no one wants to admit to negligence, particularly to the police. Later, as the investigation proceeded, he would find it increasingly embarrassing. An act of carelessness would grow into a deception. He might even have lied to cover it up.

Human frailty seemed a stronger bet than mechanical wizardry. Ingenious locked room puzzles were the province of detective story writers.

He went across to the divers. They had unpeeled their wet suits and were stacking their van. He had another job for them tomorrow, he told them, further along, by the Avoncliff Aqueduct. A bunch of keys. They didn't sound overjoyed. With a wink at the constable on duty, he stepped briskly along the towpath. This stretch of waterway now used for mooring was historically the route taken by the barges transporting coal from the Somerset mines. Much more narrow than the main canal, almost two centuries old and edged with ancient flag-stones, it had its own character, though the aluminum lift-bridge where it joined the Kennet and Avon was clearly a modern replacement. He stood for a moment staring at this bridge, deciding how the lifting mechanism worked. Clearly it had to be raised for anything the size of a narrowboat to pass under. There were counterweights projecting from the fulcrum, but the walkway was bolted down on the opposite side. He hauled on it to make sure. At this late hour nothing was about to pass into the boatyard, so his curiosity had to be set aside. He turned and started back toward the solitary policeman.

The question of most interest to him now was the one Milo had raised only a few minutes ago: What could have induced Sid Towers to visit the Mrs. Hudson? It was strange behavior considering that Milo himself was not going to be present. Why visit a locked boat after dark? One possible explanation was that the murderer had suggested meeting him there. If it was a trap, what was the bait? Or was it a threat? Maybe Sid had been under some pressure to obey the summons.

Blackmail?

He stepped aboard the narrowboat and found Milo in the cabin filling carrier bags with clothes. 'I'm about ready.'

'Good. It's cold in here. I don't know how you put up with it.'

'Well, I've got no heating on. Normally it can be really snug.'

'I walked to the end of the canal,' said Diamond. 'As far as that lift-bridge. It is a lift-bridge?'