Once I. O. examined, Is it legal to examine remain witness ?

Examination of witness does not depend on the status or kind of witness but depend on the kind of person if his evidence appears to be essential to the just decision of the case.

Prosecution can examine any prosecution witness  ranked or serialised in the charge sheet at any stage of trial in spite of their rank or serial number in memorandum of evidence. But examination of investigating officer initially and examination of other witnesses then shall cause prejudice to the accused if there is contradictions and omissions in the deposition of the witnesses and examination of investigating officer initially prevented defence to confront it before him. There is no illegality in examination of IO first and examining other winesses later.

Initially in a criminal trial firstly all witnesses are examined then i.o comes,because if any contradiction appears that should be taken from i.o.But if i.o comes prior to any vital witness and contradiction appears then defence can pray for recall of i.o u/s311 cr p c and if the court is satisfied that for the ends of justice recalling is nesessary ,court can allow the recall prayer.In fact in all cases i.o appears as last prosecution witness,though there is no illegality in calling i.o earlier.This is the rule of prudence or practice.

If witnesses are examined later, then the I.O who was examined earlier is to be recalled to put omission and contradictions of witnesses examined later.

Agree with Mr. Indrajeet.