icular reason?""That I can't say," said Tarling. "But please don't let it worry you, Mrs. Rider. She probably changed her mind at the last moment and is staying with friends in town.""Then you haven

ome very often," he explained. "By all accounts she doesn't get on with her father.""Her father? I did not know she had a father," said Tarling in surprise.Yes, there was a father. He was an infrequent visitor, and usually came up from London by the late train and was driven in his own brougham to the house. He had not seen him--indeed, very few people had, but by all accounts he was a very nice man, and well-connected in the City.Tarling had telegraphed to the assistant who had been placed at his disposal by Scotland Yard, and Detective-Inspector Whiteside was waiting for him at the station."Any fresh news?" asked Tarling."Yes, sir, there's rather an important clue come to light," said Whiteside. "I've got the car here, sir, and we might discuss it on the way back to the Yard.""What is it?" asked Tarling."We got it from Mr. Lyne's manservant," said the inspector. "It appears that the butler had been going through Mr. Lyne's things, acting on instructions from headquarters, and in a corner of his writing-desk a telegram was discovered. I'll show it you when I get to the Yard. It has a very important bearing upon the case, and I think may lead us to the murderer."On the word "telegram" Tarling felt mechanically in his pockets for the wire which Mrs. Rider had given him from her daughter. Now he took it out and read it again. It had been handed in at the General Post Office at nine o'clock exactly."That's extraordinary, sir," Detective-Inspector Whiteside, sitting by his side, had overlooked the wire."What is extraordinary?" asked Tarling with an air of surprise."I happened to see the signature to that wire--'Odette,' isn't it?" said the Scotland Yard man."Yes," nodded Tarling. "Why? What is there extraordinary in that?""Well, sir," said Whiteside, "it's something of a coincidence that the telegram which was found in Mr. Lyne's desk, and making an appointment with him at a certain flat in the Edgware Road, was also signed 'Odette,' and," he bent forward, looking at the wire still in the astonished Tarling's hand, "and," he said in triumph, "it was handed in exactly at the same time as that!"An examination of the telegram at Scotland Yard left no doubt in the detective's mind that Whiteside had spoken nothing but the truth. An urgent message was despatched to the General Post Office, and in two hours the original telegrams were before him. They were both written in the same hand. The first to her mother, saying that she could not come; the second to Lyne, running:"Will you see me at my flat to-night at eleven o'clock? ODETTE RIDER."Tarling's heart sank within him. This amazing news was stunning. It was impossible, impossible, he told himself again and again, that this girl could have killed Lyne. Suppose she had? Where had they met? Had they gone driving together, and had she shot him in making the circuit of the Park? But why should he be wearing list slippers? Why should his coat be off, and why should the night-dress be bound round and round his body?He thought the matter out, but the more he thought the more puzzle