The Code of Criminal Procedure, 1973 (CrPc)
311. Power to summon material witness, or examine person present.
Any court may, at any stage of any inquiry, trial or other proceeding under this Code, summon any person its a witness, or examine any person in attendance, though not summoned as a witness, or recall and re-examine any person already examined; and the court shall summon and examine or recall and re-examine any such person if his evidence appears to it to be essential to the just decision of the case.