Sergeant Lee tapped the side of her head. "By using ze little grey cells," she said, in a halfway passable French accent.
Inspector Zhang smiled. "Exactly," he said. "Now, in his book 'The Hollow Man', itself a locked room mystery, John Dickson Carr used Dr. Fell to expound his seven explanations that lead to a locked room murder." He nodded at his Sergeant. "You might want to make a note of them, Sergeant Lee," he said. "Now come with me." They went back into the sitting room. Miss Berghuis was sitting on the sofa next to Mercier. The waiter was standing close to the door as if he was keen to get out of the suite as quickly as possible. The two assistant managers stood by the desk in the corner of the room, looking at each other nervously.
Inspector Zhang walked to the window and stood with his back to it. "So, I have now examined the CCTV footage covering the corridor outside this room, and I have examined the crime scene." Sergeant Lee fumbled for her notebook as Inspector Zhang continued. "The CCTV footage shows that Mr. Wilkinson arrived at his room with a guest at eight-thirty and that his guest, a young woman who is known to the police, left exactly one hour later. What I need to know is when Mr. Wilkinson ordered from room service."
"That will be on the bill, inspector," said Miss Berghuis. She went over to the trolley and picked up a small leather folder and took out a slip of paper. She studied it, and nodded. "The order was placed at nine thirty-six," she said.
"Excellent," said the inspector. "So from that we can assume that Mr. Wilkinson was killed sometime between the placing of the order at nine thirty-six and the arrival of the order at nine fifty-five." He frowned. "That does seem remarkably quick, Miss Berghuis."
The manager smiled. "Inspector, we are a five-star hotel. And Mr. Wilkinson ordered only a club sandwich and a pot of coffee. Hardly a challenge for our chefs."
"Very good," said the inspector, as Miss Berghuis went back to sit on the sofa. "We can therefore rule out Mr. Wilkinson's guest as the killer, as we know for sure that he was still alive at nine thirty-six."
Miss Xue nervously raised her hand. "Actually, Inspector, we know that he was alive after that because he spoke to his wife at about a quarter to ten," she said.
"How so?" asked Inspector Zhang.
"She phoned at nine forty-five," said Miss Xue. "I was on the desk and I was there when the call came through from America. Mrs. Wilkinson was on the phone to her husband for almost five minutes."
"Are you sure?" asked the inspector.
"I am sure that it was his wife, and they spoke for several minutes," she said. "Whether it was for three, four or five minutes I am not sure."
Inspector Zhang nodded. "Then we can assume that it was indeed Mr. Wilkinson that she spoke to," he said. "I cannot believe that a wife could be fooled by an imposter. So we therefore know that Mr. Wilkinson was alive just five minutes before the waiter arrived at his door. Yet we know for a fact that no one entered the room prior to the arrival of the waiter." He drew himself up to his full height of five-feet seven inches and looked in turn at the faces of everyone in the room. "That means that what we have here is what we detectives refer to as a Locked Room Mystery."
He paused for several seconds, nodding wisely before continuing. "As I was explaining to my colleague earlier, there are basically seven explanations as to how a body can be found in a locked room. Explanations provided by the talented mystery writer John Dickson Carr. I think it would be helpful to run through them. The first possibility is that the murder is in fact not a murder, but a series of coincidences or accidents that give the impression that a crime has been committed. A man stumbles and hits his head on a piece of heavy furniture, for instance. Then we have a body, but no weapon and no killer." Inspector Zhang paused to make sure that he had everyone’s attention before continuing. "In this case, an accident is unlikely, considering the nature of the wound and the fact that the body is lying down. Plus the blood is only on the bed. If he accidentally stabbed himself on for instance the lamp on the bedside table, we would see blood on it. There is no blood anywhere but the bed, so it is safe to say that it is on the bed that he died."
He turned to look out of the window and linked his fingers behind his back. His spine clicked as he straightened it, and he sighed. "The second explanation is that it is indeed a murder, but a murder in which the victim is compelled to kill himself. Or herself. A mind-altering substance can be used, a gas or a pill, LSD for instance. Mr. Carr suggested that a man might become so bewildered that he could strangle himself with his bare hands, but of course we know that is impossible."
"You think he was drugged?" said Mercier. "Or gassed? How could gas get into the room, we have central air conditioning and the windows are sealed."
"If he was drugged, the Forensics Department would know," said Sergeant Lee. "They could perform tests."
"He did not stab himself to death," said Inspector Zhang quickly. "If he did, the weapon would be in his hands. Or on the bed. There is no knife; therefore he did not kill himself. And I see no evidence that the victim consumed food or drink in this room."
He went over to the mini-bar and opened it. It was full. "You see, nothing has been taken from the mini-bar, and there are no unopened bottles in the room."
He looked over at the room service waiter. "Mr. Wilkinson was dead when you got here? He was dead on the bed and you saw the blood?"
The waiter nodded.
"So he did not consume anything that the waiter brought into the room. We can rule out poison or drugs." He went back to the window. "It is the third explanation that creates some of the most fascinating fictional locked room mysteries," he continued. "That is where it is murder, and the killer uses some sort of mechanical device to carry out the killing. A gun concealed in a phone, for example. Or a knife that springs out of a suitcase. Or a pistol that fires when a clock is wound, or a weight that swings from the ceiling, a chair that exhales a deadly gas when your body warms it." He waved a hand at the bedroom. "In this case we would be looking for some way of stabbing Mr. Wilkinson and making the knife vanish." He smiled at his Sergeant. "What do you think, Sergeant Lee? Do you think there is a mechanical device hidden in the bedroom?"
"It is unlikely," she said quietly, as if she feared giving him the wrong answer.
"I agree," said Inspector Zhang. "It is a hotel room, like any other." The Sergeant smiled with relief.
"It is a suite, one of our best," said the manager.
Inspector Zhang nodded, acknowledging the point. "But nothing in the room has been changed, am I correct? Everything is as it should be?"
"Other than the body on the bed, yes."
"Then we shall move on to the fourth explanation. Suicide."
"Suicide?" repeated the Sergeant. "But if he stabbed himself, where is the weapon?"
"The point of the suicide is to make it look like a murder," said Inspector Zhang. "Either to throw suspicion on someone or to defraud an insurance company. I assume that a wealthy person such as Mr. Wilkinson would have a lot of insurance. Perhaps he has an incurable condition. Cancer perhaps. So he kills himself in such a way that his wife can still claim the insurance."
"Perhaps that’s it," said Mercier. "Surely you check to see if he had any policies."
"But where is the weapon he used?" asked the Sergeant. "If Mr. Wilkinson took his own life, where is the knife?"
"But that is the point exactly," said Inspector Zhang. "To make it appear to be a murder and not a suicide, the weapon must disappear. Mr. Carr suggested a knife made of ice. The ice would then melt leaving only water behind. Or a gun could be attached to a length of elastic which would then whip the gun up a chimney or out of a window."