Loan Company President's Murder Case

Situation
Kogoro, Conan, Ran, and some of Kogoro's friends are at a Mah Jong hall. One of his friends leave so now they're missing a player. They call Hida who says he'll be there in half an hour. He doesn't show so the gang goes to investigate. They run into Minamizawa who says he forgot his cell phone. They go to check on Hida who's dead. He suffocated because of potassium cyanide poisoning. The doors and the window of the room were locked.

Resolution
« Hide spoilersConan tranquilizes Kogoro and start his deduction. He tells them that the culprit manage to make the victim touch a certain thing laded with poison. The culprit did that by using a certain item that would provoke a concrete action with no possible error.

Inspector Megure thought of the telephone. If there's a call, everybody answers the phone. Minamizawa came to the office looking for his forgotten mobile phone. From that, Megure suspects him to have made a phone call from the outside so that Hida had to touch the phone which is laded with poison. However, Minamizawa is not the killer because he has a habit of biting his nails and in spite of this, when he came back, he took his phone barehanded. If there had been poison on the phone, he wouldn't have taken the risk to do that. He couldn't know which part of the phone Hida had touched. Moreover, it would have been impossible to know which hand Hida would use to take the phone. In addition, Hida could have taken the poisoned phone into his office, and that was a risk. This is the proof that Minamizawa is not the culprit.

Inspector Megure then thought of the computer. He said that the culprit put the poison on the power button and phoned the victim to ask him to check a document in the computer. Megure then suspects Iino. He said that Iino removed the poison by pretending to check the data in the computer. Again, Conan as Kogoro told him that Iino is not the culprit because there is no way he could have known beforehand that his boss would boot on the computer with his thumb. Furthermore, the poison could have spread to the keys of the keyboard if Hida had touched them. In addition, when Iino was verifying his data, several policemen were watching him. It would have been impossible to clean all the keyboard without being noticed. This is the proof that Iino is not the culprit.

Kogoro then points that there is one thing, an unstoppable way to put in contact the right thumb and the poison with no possible doubt. He explains that the victim heard the whistle noise of the kettle in the kitchen and went to turn off the knob. The murderer put the poison on the knob of the cooker beforehand. Most cookers are made for right-handed people. It's difficult to turn the knob with the left hand. It was only necessary to put the poison on the left side of the knob. It was clear that Hida would put his right thumb there in order to turn off the fire. And, as a proof, the poison was only found on the inner handle of the door, and not on the outer handle because Hida left his office hastily leaving the door open, he touched the poison, went back to his office and locked the door. Hida was a mistrustful person, and he wouldn't have panicked because of a simple phone call. Kogoro then points out that the only person who was near the cooker after the body was found was Takako Fuji. Just before leaving the office, you put a whistle kettle on the fire so that the whistle sounded while Hida was counting the money. And, as she had foreseen, Hida was frightened by the whistle, touched the poisoned knob, and, later on, he licked the poison. She had planned to clean the poison tomorrow morning when she came to the office, but the corpse was found before than expected and the police arrived but she were afraid that they could find the poison traces. She used the moment when the policemen abandoned the kitchen to erase the poison, pretending to make some tea. Kogoro then points out that she used handkerchief and bleaching agent to erase completely the traces of poison in such a short time. Megure then put some iodine on her wet handkerchief and the color has disappeared. Kogoro then said that Takako's handkerchief was wet not because of water or sweat, but instead of bleaching agent. Bleaching agent is commonly used in medicine to clean the remains of disinfectant and it's also an antidote against the poison used in the crime. It neutralizes all the effects of cyanide. This is the proof that Takako is the one who erased the poison. Kogoro then points out that there still some bleaching agent left in the locker of the toilet. It's a product capable of bleaching at room temperature. He then said that after Takako's arrival, she went to the toilet to wet her handkerchief with the bleaching agent and then waited until she was able to remove the remaining poison on the knob of the cooker. Not only has she cleaned the poison, but also has changed its nature by means of that product in order to make it impossible to be discovered. She has deceived the police. Kogoro then said that the bleaching agent is colorless and odorless. Even if the handkerchief is wet, the police can think it is just water. Also, that product is not sold at normal chemist's. The fact of finding it in the toilet is surprising. Also, the fact that Fuji's handkerchief was soaked in bleaching agent, the product is found on the toilet, and she kept a wet handkerchief is the evidence that she is the culprit.

Fuji admitted the murder. Her boyfriend borrowed Hida some money and couldn't pay it back. Her boyfriend hung himself soon after. She then found out that her boyfriend borrowed money for her. Since she was a child, she suffered a heart disease. She had to be in a hospital since she left university three years ago. Her parents had died and, because of her bad temper, she had no friends. Only her boyfriend went to see her in the hospital. Her boyfriend told her to be brave because he was going to bear the expenses of her illness. She got over and went to visit him to his flat, where she found him hanging from the ceiling. The contract of the loan granted by "Hida Finances" was lying under his feet. It turns out that she joined the company with the only purpose of taking revenge. She waited during all those time for the moment to come. Another proof that she is the culprit is because of her left hand, which was always in her pocket. When she take a cigarette, when she use her lighter, when she take an object, she only use her right hand. She used her left hand once: when she turned the knob of the cooker. She is a heavy smoker, her fingers touch her lips, she were afraid of that, so she deliberately turned the knob with your left hand because, even though she had cleaned the poison, it couldn't be assured that no poison remained. If she didn't take her left hand out of her pocket, it was because she didn't want to touch anything. Luckily, only her left hand fingerprints were found on the knob of the cooker. It was difficult to turn it with left hand. Fuji is soon arrested.

Three days later, Ran becomes addicted in playing mahjong much to Conan and Kogoro's surprise.