Jisatsu sâkuru or Suicide Club (2001) (Japanese)

[Friday The 13th]

In Tokyo, when fifty-four high-school students commit a collective suicide, jumping from a platform in Shinjuku Station, the police force leaded by Detective Kuroda has no clue to follow. Then he receives an e-mail from a young woman, The Bat, advising that there is a site where red dots mean the number of persons that died. Kuroda and his team investigate the deaths going nowhere.