CRIMINOLOGISTS from Hong Kong, Beijing and Taiwan are set to join forces this week in a new research group on cross-border crime. Formation of the Hong Kong Macau Crime Research Committee is expected to be formally announced tomorrow at a conference of crime researchers. Conference organiser Dr Che Wai-kin, senior lecturer in the social sciences department of Lingnan College, said: ''The committee would be very important because it would be able to compare and link research projects in Hong Kong, Taiwan and the mainland.'' The committee will be chaired by Zhang Niqun, head of the China Youth Crime Research Association in Beijing. ''We are hoping he will be able to invite the Public Security Bureau to be a member of the committee so that they can share information about crime with us,'' Dr Che said.