Which is the most possible reason for such a disaster?

News Item 2
    A fire broke out in a Buenos Aires nightclub, which packed with young revelers celebrating the New Year holidays. It killed at least 175 people when a crowd was trapped by locked doors, officials said on Friday. At least 619 people were injured in the blaze, after a flare fired into the club’s ceiling during a rock concert. (8) The blaze may have claimed more victims because four of the club’s six doors were Inexplicably tied shut with wire.