IMMIGRATION POLICE say they know who was behind the mass escape of 18 Rohingya from the Phang Nga shelter on July 21 and are closing in on them. Phang Nga and Ranong immigration officers on Wednesday night took into custody a Rohingya woman and four children on a Bangkok-bound train."The woman was assisted by people outside the shelter.They told her they were sent by relatives and were there to help,"Phang Nga immigration chief Neti Khanboon said. At this stage we know of two to three gangs who do this. They always pretend to be relatives or claim to be helping and that relatives were waiting for them." The womand and the children have returned to the shelter, where they have been for eight months.