“Yes, sir,” he said, in answer to Reeder’s inquiry, “I think it was loaded. It went very heavily on the road. We often get these lorries coming up from Shoeburyness.”
Simpson had put through a telephone inquiry to the Barking police, who had seen the military wagon. But army convoys were no unusual sight in the region of the docks. Either that or one similar was seen entering the Blackwall Tunnel, but the Greenwich police, on the south side of the river, had failed to identify it, and from there on all trace of the lorry was lost.
“We’re probably chasing a shadow anyway,” said Simpson. “If your theory is right, Reeder—but it can’t be right! They couldn’t have caught these men of ours so unprepared that somebody didn’t shoot, and there’s no sign of shooting.”
“There was no shooting,” said Mr. Reeder, shaking his head.
“Then where are the men?” asked Simpson.
“Dead,” said Mr. Reeder quietly.
It was Scotland Yard, in the presence of an incredulous and horrified commissioner, that Mr. J. G. Reeder reconstructed the crime.
“Flack is a chemist; I think I impressed it upon you. Did you notice, Simpson, on the bridge across the cutting an old water cart? I think you have since learned that it does not belong to the farmer who owns the land, and that he has never seen it before. It may be possible to discover where that was purchased. In all probability you will find that it was bought a few days ago at the sale of some municipal stores. I noticed in the Times there was an advertisement of such a sale. Do you realize how easy it would be not only to store under pressure, but to make, in that tank, large quantities of a deadly gas, one important element of which is carbon monoxide? Suppose this, or, as it may prove, a more deadly gas, has been so stored, do you realize how simple a matter it would be on a still, breathless morning to throw a big hose over the bridge and fill the hollow with the gas? That is, I am sure, what happened. Whatever else was used, there is still carbon monoxide in the cutting, for when I dropped a match it was immediately extinguished, and every match I struck near the ground went out. If the car had run right through and climbed the other slope of the cutting, the driver and the men inside the lorry might have escaped death. As it was, rendered momentarily unconscious, the driver turned his wheel and ran into the bank, stopping the lorry. They were probably dead before Flack and his associate, whoever it was, jumped down, wearing gas masks, lifted the driver back into the lorry and drove on.”
“And the farmer—” began the commissioner.
“His death probably occurred some time after the lorry had passed. He also descended into that death hollow, but the speed at which his car was going carried him up nearer the cutting, though he must have been dead by the time he got out.”
He rose and stretched himself wearily.
“Now I think I will go and interview Miss Belman and set her mind at rest,” he said. “Did you send her to the hotel, as I asked you, Mr. Simpson?”
Simpson stared at him in blank astonishment.
“Miss Belman?” he said. “I haven’t seen Miss Belman!”
XIV
Her head in a whirl, Margaret Belman had stepped into the cab that was waiting at the door of Larmes Keep. The door was immediately slammed behind her and the cab moved off. She saw her companion; he had shrunk into a corner of the landau, and greeted her with a little embarrassed grin. He did not speak until the cab was some distance from the house.
“My name’s Gray,” he said. “Mr. Reeder hadn’t a chance to introduce me. Sergeant Gray, C.I.D.”
“Mr. Gray, what does all this mean—this instrument I am to get?”
Gray coughed. He knew nothing about the instrument, he explained, but his instructions were to put her into a car that would be waiting at the foot of the hill road.
“Mr. Reeder wants you to go up by car. You didn’t see Brill anywhere, did you?”
“Brill?” she frowned. “Who is Brill?”
He explained that there had been two officers inside the grounds, himself and the man he had mentioned.
“But what is happening? Is there anything wrong at Larmes Keep?” she asked.
She had no need to ask the question. That look in J. G. Reeder’s eyes had told her that something indeed was very wrong.
“I don’t know, miss,” said Gray diplomatically. “All I know is that the Chief Inspector is down here with a dozen men and that looks like business. I suppose Mr. Reeder wanted to get you out of it.”
She didn’t “suppose,” she knew, and her heart beat a little quicker.
What was the mystery of Larmes Keep? Had all this to do with the disappearance of Ravini? She tried hard to think calmly and logically, but her thoughts were out of control.
The landau stopped at the foot of the hill, and Gray jumped out. A little ahead of him she saw the tail light of a car drawn up by the side of the roadway.
“You’ve got the letter, miss? The car will take you straight to Scotland Yard, and Mr. Simpson will look after you.”
He followed her to the car and held open the door for her, and stood in the roadway watching till the tail light disappeared round a bend of the road.
It was a big, cosy landaulette, and Margaret made herself comfortable in the corner, pulled the rug over her knees, and settled down to the two hours’
