Inspector-General of Police Tan Sri Razarudin Husain said the police raided the house of the suspect, who was in his 30s, in Ulu Tiram and detained five of his family members, aged between 19 and 62.
"I have also instructed the Special Branch division to track down and identify Jemaah Islamiyah members in this state, estimated to be more than 20 people," he told a press conference at the scene.
Two policemen were killed while another was injured in the 2.45 am incident.