law: Indian Evidence Act, 1872 
  24. Confession caused by inducement, threat or promise
  
  when irrelevant in criminal proceedings
  A confession made by
  
  an accused person is irrelevant in a criminal proceeding, if the making of the
  
  confession appears to the Court to have been caused by any inducement, threat
  
  for promise, having reference to the charge against the accused person,
  
  proceeding from a person in authority and sufficient, in the opinion of the
  
  Court, to give the accused person grounds, which would appear to him
  
  reasonable, for supposing that by making it he would gain any advantage or
  
  avoid any evil of a temporal nature in reference to the proceedings against
  
  him.