(1) The Advisory Board shall, after considering the materials placed before it and, after calling for such further information as it may deem necessary from the appropriate Government or from any person called for the purpose through the appropriate Government or from the person concerned, and if, in any particular case, it considers it essential so to do or if the person concerned desires to be heard, after hearing him in person, submit its report to the appropriate Government within seven weeks from the date of detention of the person concerned.