Mikami confesses to his crime and reveals that Osamu stole his manuscript and published the book as his own .
As evidence , Conan reveals that Osamu managed to rip a button from Mikami 's shirt and using the gum he had , stuck it onto the sofa .
Mikami confesses to Conan 's crime and reveals Osamu Osamu stole his manuscript and published the book as his own .
As evidence , Conan reveals that Osamu managed to rip a button from Mikami 's shirt and using the gum he had , stuck it onto the sofa .