Murder on the 31st Floor Part I (1979)

Police officer Jensen tells to evacute the whole building of a leading media group after a bomb threat is made. There won't be any explosion; however, the media group sustains big losses because of the work stoppage and the management requires investigation of the case and makes no public notice about it. Officer Jensen identifies six suspects, then finds out that he is being followed himself, especially when he gets involved in the obscure activities of the 31st floor. Investigations lead to confessions and the case will be closed. The one who pleads himself guilty suddenly dies in the detention room. Further investigation makes it evident that the whole society is in danger.