This article is about an episode of the Detective Conan anime that has not yet aired. As such, it is a reflection of what is currently known about the episode. More information will be added after the episode aired.
The culprit is Saya Kitami, and she is actually 29 years old. She used a recording of Sakurako to lure Kyona into opening the door for her. The murder weapon was Kyona Shono's selfie stick, which Saya took to her own apartment. To close Kyona's apartment door and leave the card inside, she used her toy helicopter. Her motive was that she thought Kyona knew she had accidentally killed an old man in a car accident and fled the crime scene, but in fact the only secret Kyona knew was that Saya was actually 5 years older than she claimed to be.
Afterwards, Hyoue Kuroda arrives on the scene, announces that Kiyonaga Matsumoto has been promoted, and that he will be taking his place. Conan looks on in shock and Ai grips his shoulder in fear, as Kuroda asks for Conan's assistance in his new position.