The suspects in this case are not so much, so I added some innocent people to make it funny.
The first suspect is the victim herself, Kawauchi Misato (The reporter herself). It's possible that she stabbed herself to accuse Shinichi.
The second suspect is Kudo Shinichi. He was holding the knife
and was standing in the crime scene Another suspicious person is Hattori Heiji. He was sleeping with Shinichi in the same room, so he could have put him to sleep by a drug, curried him to that house, and stabbed the reporter. The motive is of course because Heiji wants to stands out as a high school detective.
Next suspect is Hikawa Moegi (Makoto's classmate). The motive is the same as Kawauchi Misato (the reporter), although I don't understand why she wants to hurt the reporter.
Makoto who has disappeared is also a suspect, and he has similar motive.
Shiroyama Kazuma (The policeman) is also suspicious because it looked like he didn't want the reporter to say the thing which should not be said. Until now, we don't know what that thing is, but even if he was the one who did it, I don't understand why he had to make it as if Shinichi was the one who did it.
Finally, Daiki, the young master, called Shinichi a lier at the beginning of the case. So he has the same motive as Hikawa Moegi & Makoto which is blaming Shinichi for stabbing the reporter.
with knives and he seals that room very tightly by nailing it with a bunch of wooden plates. He probably also had a plastic surgery to look like Shinichi and has been living in that hut as Shiragami-sama for half a year. He pretends he has amnesia because it gives him the excuse of not knowing everyone he's around with so he doesn't have to be able to recognize who they are because he isn't Shinichi. He was going to kill Shinichi and live as the new Shinichi, but since the reporter found out about what he was trying to do and was about to report it, he tried to kill her. The real Shinichi called police and ambulance before Hattori and his fellows because he's observing the fake one from the forest. He's wearing a wig so people wouldn't get confused that there are two Shinichi's, which might cause a lot of problem because people would know the real Shinichi is alive, which might cause a lot of problems if gone public. 
