S (SUZUKI Koji; Novel)

From Kodansha: 28-year-old image processing specialist Takanori Ando being handed a USB memory stick by the president of the CG production company where he works. Tasked with analyzing its contents, Ando gasps at the graphic images he sees, and quickly concludes that they cannot have been faked or generated by CG software. Assuming the man in the video did indeed kill himself, what could his purpose have been in leaving this footage behind? Ando saves the file to his PC. When he plays it again the next day, the man's body has shifted to a lower position, and in subsequent viewings, the video undergoes further changes.