Inspector Crome was in his office at Scotland Yard.

The telephone on his desk gave a discreet buzz and he picked it up.

"Jacobs speaking, sir. There's a young fellow come in with a story that I think you ought to hear."

Inspector Crome sighed. On an average twenty people a day turned up with so-called important information about the A.B.C. case. Some of them were harmless lunatics, some of them were well-meaning persons who genuinely believed that their information was of value. It was the duty of Sergeant Jacobs to act as a human sieve—retaining the grosset matter and passing on the residue to his superior.

"Very well, Jacobs," said Crome. "Send him along."

A few minutes later there was a tap on the inspector's door and Sergeant Jacobs appeared, ushering in a tall, moderately good-looking young man.

"This is Mr. Tom Hartigan, sir. He's got something to tell us which may have a possible bearing on the A.B.C. case."

The inspector rose pleasantly and shook hands.

"Good morning, Mr. Hartigan. Sit down, won't you? Smoke? Have a cigarette?"

Tom Hanigan sat down awkwardly and looked with some awe at what he called in his own mind "one of the bigwigs." The appearance of the inspector vaguely disappointed him. He looked quite an ordinary person.

"Now then," said Crome. "You've got something to tell us that you think may have a bearing on the case. Fire ahead."

Tom began nervously. "Of course it may be nothing at all. It's just an idea of mine. I may be wasting your time."

Again, Inspector Crome sighed imperceptibly. The amount of time he had to waste in reassuring people!

"We're the best judge of that. Let's have the facts, Mr. Hartigan."

"Well, it's like this, sir. I've got a young lady, you see, and her mother lets rooms. Up Camden Town way. Their second floor back has been let for over a year to a man called Cust."

"Cust—eh?"

"That's fight, sir. A sort of middle-aged bloke what's rather vague and soft—and come down in the world a bit, I should say. Sort of creature who wouldn't hurt a fly, you'd say—and I'd never of dreamed of anything being wrong if it hadn't been for something rather odd."

In a somewhat confused manner and repeating himself once or twice, Tom described his encounter with Mr. Cust at Euston Station and the incident of the dropped ticket.

"You see, sir, look at it how you will, it's funny like. Lily, that's my young lady, sir—she was quite positive that it was Cheltenham he said, and her mother says the same—says she remembers distinctly talking about it the morning he went off. Of course, I didn't pay much attention to it at the time. Lily—my young lady said as how she hoped he wouldn't cop it for this A.B.C. fellow going to Doncaster—and then she says it's rather a coincidence because he was down Churston way at the time of the last crime. Laughing like, I asks her whether he was at Bexhill the time before, and she says she don't know where he was, but he was away at the seaside—that she does know. And then I said to her it would be odd if he was the A.B.C. himself and she said poor Mr. Cust wouldn't hurt a fly—and that was all at the time. We didn't think no more about it. At least, in a sort of way I did, sir, underneath like. I began wondering about this Cust fellow and thinking that, after all, harmless as he seemed, he might be a bit batty."

Tom took a breath and then went on. Inspector Crome was listening intently now.

"And then after the Doncaster murder, sir, it was in all the papers that information was wanted as to the whereabouts of a certain A.B. Case or Cash, and it gave a description that fitted well enough. First evening off I had, I went round to Lily's and asked her what her Mr. Cust's initials were. She couldn't remember at first, but her mother did."

"Said they were A.B. right enough. Then we got down to it and tried to figure out if Cust had been away at the time of the first murder at Andover. Well, as you know, sir, it isn't too easy to remember things three months back. We had a job of it, but we got it fixed down in the end, because Mrs. Marbury had a brother come from Canada to see her on June 21^st. He arrived unexpected like and she wanted to give him a bed, and Lily suggested that as Mr. Cust was away Bert Marbury might have his bed. But Mrs. Marbury wouldn't agree, because she said it wasn't acting right by her lodger, and she always liked to act fair and square. But we fixed the date all right because of Bert Marbury's ship docking at Southampton that day."

Inspector Crome had listened very attentively, jotting down an occasional note.

"That's all?" he asked.

"That's all, sir. I hope you don't think I'm making a lot of nothing." Tom flushed slightly.

"Not at all. You were quite right to come here. Of course, it's very slight evidence—these dates may be mere coincidence and the likeness of the name, too. But it certainly warrants my having an interview with your Mr. Cust. Is he at home now?"

"Yes, sir."

"When did he return?"

"The evening of the Doncaster murder, sir."

"What's he been doing since?"

"He's stayed in mostly, sir. And he's been looking very queer, Mrs. Marbury says. He buys a lot of newspapers—goes out early and gets the morning ones, and then after dark he goes out and gets the evening ones. Mrs. Marbury says he talks a lot to himself, too. She thinks he's getting queerer."

"What is this Mrs. Marbury's address?"

Tom gave it to him.

"I thank you. I shall probably be calling round in the course of the day. I need hardly tell you to be careful of your manner if you come across this Cust."

He rose and shook hands.

"You may be quite satisfied you did the right thing in coming to us. Good morning, Mr. Hartigan."

"Well, sir?" asked Jacobs, re-entering the room a few minutes later. "Think it's the goods?"

"It's promising," said Inspector Crome. "That is, if the facts are as the boy stated them. We've had no luck with the stocking manufacturers yet. It was time we got hold of something. By the way, give me that file of the Churston case."

He spent some minutes looking for what he wanted. "Ah, here it is. It's amongst the statements made to the Torquay police. Young man of the name of Hill. Deposes he was leaving Torquay Pavilion after the film Not a Sparrow and noticed a man behaving queerly. He was talking to himself. Hill heard him say, 'That's an idea.' Not a Sparrow—that's the film that was on at the Regal in Doncaster?"

"Yes, sir."

"There may be something in that. Nothing to it at the time—but it's possible that the idea of the modus operandi for his next crime occurred to our man then. We've got Hill's name and address, I see. His description of the man is vague but it links up well enough with the descriptions of Mary Stroud and this Tom Hartigan . . . ."

He nodded thoughtfully.

"We're getting warm," said Inspector Crome—rather inaccurately, for he himself was always slightly chilly.

"Any instructions, sir?"

"Put on a couple of men to watch this Camden Town address, but I don't want our bird frightened. I must have a word with the A.C.. Then I think it would be as well if Cust was brought along here and asked if he'd like to make a statement. It sounds as though he's quite ready to get rattled."

Outside Tom Hartigan had rejoined Lily Marbury who was waiting for him on the Embankment.