law: The National Investigation Agency Act, 2008
  7. Power to transfer
  
  investigation to State Government. -
  While investigating
  
  any offence under this Act, the Agency, having regard to the gravity of the
  
  offence and other relevant factors, may-
  a.  
  
    if
  
  it is expedient to do so, request the State Government to associate itself with
  
  the investigation; or
  b.  
  
    with
  
  the previous approval of the Central Government, transfer the case to the State
  
  Government for investigation and trial of the offence.