Supreme Court on Non-Examination of Investigating Officer (IO)

“18. Keeping in view the aforesaid position of law, the testimony of PW 1 has to be appreciated. He has admitted his signature in the FIR but has given the excuse that it was taken on a blank paper. The same could have been clarified by the investigating officer, but for some reason, the investigating officer has not been examined by the prosecution. It is an accepted principle that non-examination of the investigating officer is not fatal to the prosecution case. In Behari Prasad v. State of Bihar [(1996) 2 SCC 317: 1996 SCC (Cri) 271], this Court has stated that non-examination of the investigating officer is not fatal to the prosecution case, especially, when no prejudice is likely to be suffered by the accused. In Bahadur Naik v. State of Bihar [(2000) 9 SCC 153: 2000 SCC (Cri) 1186] , it has been opined that when no material contradictions have been brought out, then non-examination of the investigating officer as a witness for the prosecution is of no consequence and under such circumstances, no prejudice is caused to the accused. It is worthy to note that neither the trial Judge nor the High Court has delved into the issue of non-examination of the investigating officer. On a perusal of the entire material brought on record, we find that no explanation has been offered. The present case is one where we are inclined to think so especially when the informant has stated that the signature was taken while he was in a drunken state, the panch witness had turned hostile and some of the evidence adduced in the court did not find place in the statement recorded under Section 161 of the Code. Thus, this Court in Arvind Singh v. State of Bihar, [(2001) 6 SCC 407: 2001 SCC (Cri) 1148], Rattanlal v. State of J&K [(2007) 13 SCC 18: (2009) 2 SCC (Cri) 349] and Ravishwar Manjhi v. State of Jharkhand [(2008) 16 SCC 561: (2010) 4 SCC (Cri) 50], has explained certain circumstances where the examination of investigating officer becomes vital. We are disposed to think that the present case is one where the investigating officer should have been examined and his non-examination creates a lacuna in the case of the prosecution.”

Supreme Court
Lahu Kamlakar Patil v. State of Maharashtra, (2013) 6 SCC 417