In addition , the killers claimed Statement to have investigated Criminal_investigation passengers ' cellphones and text messages to determine Deciding if they were involved Participation with the Gulf Cartel or not , and that they were particularly worried about buses coming in from the states of Durango and Michoacán , two strongholds of the rival La Familia and the Sinaloa Cartels .

This worried Malaysia as this would mean the potential use of Singapore as a communist base to spread Dispersal communism to Malaysia , over which it would not have sovereignty .