'Could've done, I suppose.' The locksmith hesitated a moment. 'From Canal Reach, officer? Number 9, perhaps?'

'Perhaps.'

'Well, I did then.'

'You've got a record of doing the job?'

The man's eyes were guarded. 'Very doubtful, I should think, after all this time. It must have been eighteen months, coupla years ago. She locked herself out one day and came in to ask for help. So I went down there and opened up for her-and I suggested that she had a couple more keys cut.'

'A couple, you say?'

'That's it.'

'I suppose most of the people round here have two to start with, don't they?'

'Most of 'em.'

'So she finished up with four,' said Walters slowly.

'Let's say that one time or another she had four different keys in her possession. Wouldn't that be slightly more accurate, officer?'

Walters was beginning to dislike the man. 'Nothing else you can tell me?'

'Should there be?'

'No, I'm sure there shouldn't.'

But as Walters was halfway through the door, the locksmith decided that there might be a little more to tell after all. 'I shouldn't be surprised if somebody else in the Reach knows something about those keys.'

'Really. Who-?'

But the locksmith had no further need of words. His right hand selected one of the numerals from the boxes in front of him, his left hand another. Then, like an international judge at a skating championship, he held his arms just above his head, and the number thus signalled was 10.

Walters walked thoughtfully back to Canal Reach and let himself into number 9 with the key that Mrs. Purvis had kept for her neighbour. It slipped easily into the socket and the tongue of the lock sprang across with a smooth but solid twang. He walked through into the kitchen, every detail of death now removed, and looked out on to the narrow back garden, where he noticed that the wall fronting the canal had recently (very recently, surely?) been repaired, with thirty or so new rosy-red bricks and half a dozen coping stones-all most professionally pointed. Then he went upstairs into the front bedroom and looked around quietly, keeping as far as he could from the line of the curtainless window. The bed was just as he had seen it before, neatly made, with the edge of the purple quilt running uniformly parallel about three inches from the floor. Would Morse have noticed anything here, he wondered? Then he suddenly stepped boldly right in front of the window-and saw what he was half expecting to see. The floral curtains of the bedroom across in number 10 had moved, albeit very slightly, and Walters felt quite sure that the room in which he stood was under a steady and proximate surveillance. He smiled to himself as he looked more closely at the houses opposite-brick-built, slate-roofed, sash-windowed, with square chimneys surmounted by stumpy, yellow pots. No tunnel-backs to the houses, and so the bicycles had to be left outside: like the bicycle just opposite. Yes… perhaps it was high time to pay a brief call at number 10, one of only two houses in the Reach at which he'd received no answer to his knocks the day before.

The door was opened almost immediately. 'Yes?'

'I'm a police officer, Mr. er-?'

'Jackson. Mr. Jackson.'

'Mind if I come in for a minute or two, Mr. Jackson?'

Here the ground floor of the house had (as at number 9) been converted into one large, single room, but in comparison it seemed crowded and dingy, with fishing paraphernalia-rods, baskets, keep-nets, boxes of hooks, and dirty-sided buckets-providing the bulk of the untidy clutter. Removing a copy of The Angler's Times, Walters sat down in a grubby, creaking armchair and asked Jackson what he knew about the woman who had lived opposite for the past two years.

'Not much really. Nice woman-always pleasant-but I never knew her personally, like.'

'Did she ever leave her key with you?'

Was there a glimmer of fright in those small, suspicious eyes? Walters wasn't sure, but he felt a little surprised at the man's hesitant reaction; even more surprised at his reply.

'As a matter of fact she did, yes. I do a few little jobs, you know-round about, like-and I did one or two things for Miss Scott.'

'She used to let you have a key for that?'

'Well, you see, she wasn't always in in the afternoons-and with me, well, not in much in the mornings, like-so I'd let meself in if-'

'Was it you who did the brick-work?'

There was no fright this time-Walters was sure of that-and perhaps he'd been wrong earlier. After all, most of the public get a little flustered when the police start questioning them.

'You saw that?' Jackson's ratty-featured face was creased with pleasure. 'Neat little job, wasn't it?'

'When did you do that?'

'This week-Monday and Tuesday afternoons it was-not a big job-about four or five hours, that's all.'

'You finished Tuesday afternoon?'

'That's right-you can ask Mrs. Purvis if you don't believe me. She was out the back when I was just finishing off, and I remember her saying what a nice and neat little job it was, like. You ask her!' The man's small eyes were steady and almost confident now.

'You've still got the key?'

Jackson shook his head. 'Miss Scott asked me to give it back to her when I'd finished and-'

'You gave it back to her, then?'

'Well, not exactly, no. She was there on the Tuesday afternoon and while she paid me, like, it must have slipped me memory-and hers, as well. But I remembered on the Wednesday, see. I'd been fishing in the morning and I got back about-oh, I don't know-some time in the afternoon, so I nipped over and-'

'You did?' Walters felt strangely excited.

'-just stuck it through the letter box.'

'Oh.' It was all as simple and straightforward as that, then; and Walters suspected he'd been getting far too sophistical about the key business. Could Jackson clear up one or two other things, as well, perhaps? 'Was the door unlocked, do you remember?'

Jackson closed his eyes for a few moments, inclining his head as though pondering some mighty problem. 'I didn't try it, I don't think. As I say, I just stuck-'

'What time was that, do you say?'

'I-I can't remember. Let's see, I must have slipped across there about-it must have been about half-past… No, I just can't seem to remember. When you're out fishing, you know, you lose all track of time, really.' Then Jackson looked up with a more obvious flash of intelligence in his eyes. 'Perhaps one or two of the neighbours might have seen me, though? Might be worth asking round, mightn't it?'

'You mean people here tend to er to pry on what all the others are doing?' Walters had chosen his words carefully, and he could see that his point had registered.

'Only a tiny little street, isn't it? It's difficult not to-'

'What I meant was, Mr. Jackson, that perhaps-perhaps you might have seen someone-someone else-going over to number 9 when you got back from your fishing.'

'Trouble is,' Jackson hesitated, 'one day seems just like any other when you're getting on a bit like I am.'

'It was only two days ago, you know.'

'Ye-es. And I think you're right. I can't be sure of the time and all that, like-but there-was someone. It was just after I'd nipped over, I think-and-yes! I'm pretty sure it was. I'd just been up to the shop for a few things-and then I saw someone go in there. Huh! I reckon I'd have forgotten all about it if-'

'This person just walked in?'

'That's it. And then a few minutes later walked out.'

Phew! Things had taken an oddly interesting turn, and Walters pressed on eagerly. 'Would you recognise him-it was a man, you say?'

Jackson nodded. 'I didn't know him-never seen him before.'