The police have already checked all of the items that resemble string and have tested for luminol. However Conan, Amuro, and Masumi reveal that the weapon has already left the studio. The police carried it out because it was one of the victims belongings. The murderer had taken her knit hat and unraveled it and used it as the murder weapon and then knitted it back together using the drumsticks. Amuro reveals that the culprit is Rumi Kogure. The other two suspects had gone into the room to do things that couldn't have been planned. Where as Rumi was supposedly playing her keyboard with her back to the camera where no one could see what she was doing. She had secretly been knitting the hat back together. With the drums fixed in place, the placement of the selfie stick camera would be dependent on the position of the keyboard. Rumi just had to move the keyboard further away from the drums so that the others would have moved the selfie stick to in front of the cctv camera. She has also spiked the victims water bottle with sleeping pills to ensure that she was asleep.
The motive was that the victim had been telling Akane to drink lots of wine and scream into a pillow to get her voice back, but in actuality it was making her voice worse. Then she told Akane that her voice was withering and that she shouldn't even show up to the next gig. Later Akane committed suicide by jumping in front of a car. However it seems that was all a misconception. Akane had run out into the road to save a small child who was crossing the road to get his ball. The victim had believed that she was responsible for Akane's death, not because of her harsh words about her voice, but because she had made a deal with her not to speak until her voice had gotten better. This was why Akane ran into the road rather then shouting, because it would hurt her voice.
After the case, Masumi revealed to Ran and Sonoko that the reason she became a detective was because of her oldest brother Shuichi, who is an FBI agent. Sonoko inquires if the person who taught Masumi the base was also from the FBI, but Masumi denies it. Amuro inwardly comments that the man was a member of the Metro Police Department Public Security Bureau and that Shuichi was the one who killed him.
Conan makes a connection between Mary and Haibara due to some remaining makeup.
The culprit is Takashi Kamaya. Kamaya confess his motive that he was dating with his girlfriend in the restaurant. When the chef goes to him and his girlfriend, he asks him that did he add the honey. He said that he add the jam, not the honey. Because it is the latest secret of the restaurant. He explains that he did used to add honey to improve the sour taste. But he switched to jam a while ago. But he is Kamaya, he used to work here. None of the others recognized him, but he sure did. A lot of the recipes here have changed. His girlfriend called him a liar and break up with him. It was because he thought that he added the honey.
Afterwards, Haibara rubs mascara off of her eye, and Conan sees that the smeared mascara makes her face look like that of the child Mary that Masumi is hiding.
