"I see!" Inspector Megure gripped the stove knob as though he had seized the truth itself. "The murderer smeared poison on this stove knob. When the victim heard the kettle while making a phone call, he hurried over to turn off the heat and got poison on his fingers.
"Then he returned to his office, locked the door, and continued counting money. When he habitually licked his fingers, he licked the poison on his thumb and died on the spot."
Jiang Xia nodded. "So, the murderer is obvious—the person who killed Mr. Fuyuki was Miss Fujii, the only one who approached the stove after the crime."
He looked at the pretty female employee whose expression had changed dramatically. "Before leaving work, you placed the Whistling Kettle filled with water on the stove, lit the fire, and applied the poison.
"Afterward, the three of you left the Detective Agency, while the victim remained behind to count the banknotes he had recovered. After counting for a while, the water in the kettle boiled. Its piercing whistle forced him to stop what he was doing and rush to the pantry to turn off the heat.
"You originally planned to wipe the poison off the stove knob when you came to work tomorrow. But because of Uncle Mouri and his mahjong-loving friends, the body was discovered far earlier than you expected.
"Watching the police inspect the scene, you realized that if this continued, the poison in the pantry would eventually be discovered. So you pretended to boil water and went over to wipe it away."
"..."
Fujii Takako took a deep breath and bit down on her cigarette. "Didn't that officer just say that poison would be difficult to wipe away completely? You found me the moment I reached the pantry. With so little