|Series:||AKB48 Murder Mystery|
|First Appearance:||File 5|
|Last Appearance:||File 5|
|Number of Episode|
|2 (File 5, Testimony File)|
- "Finding out who is the culprit is really important, but, the first priority should be getting off this island! All the members of AKB are here, so that means AKB’s theater performances will be on hold indefinitely, right? I hate missing a performance more than anything else. Ah, could it be that the culprit’s true aim is something like that?"
- ―Matsubara Natsumi's Testimonial[src]
Matsubara Natsumi (松原夏海?), nicknamed Nattsumii (なっつみぃ?), is a member of Team A. She is one of the primary characters in AKB48 Murder Mystery series. She was based on and was portrayed by Matsubara Natsumi.
All 89 members of AKB48 went to a duplex island owned by one of Akimoto Yasushi's friends for a CM Shoot. After their first day shoot was over, they went to their designated resthouse on the other island. It was assumed that she heard that Kato Rena was missing and was shocked to learn that the scream they heard was from Sashiko finding the girl's lifeless body in the dining hall.