“Mohan Lal observed, in a case where the informant and the investigator is the same, trial is vitiated and accused is entitled to acquittal. Varinder Kumar held, decision in Mohan Lal shall be applicable prospectively.
The NDPS Act does not specifically bar an informant/complainant to be an investigator. Therefore, as such, there is no reason to doubt the credibility of the informant and doubt the entire case of the prosecution solely on the ground, the informant has investigated the case. Solely on basis of some apprehension or doubts, the entire prosecution version cannot be discarded and accused is not to be straightway acquitted unless and until accused is able to establish and prove – bias and prejudice. The question of prejudice or bias has to be established and not inferred.
Therefore, merely because the informant is the investigator, investigation would not suffer the vice of unfairness or bias and accused is not entitled to acquittal. The matter has to be decided on a case to case basis. A contrary decision of this Court in Mohan Lal v. State of Punjab, (2018) 17 SCC 627 and any other decision taking a contrary view are not good law and they are specifically overruled.”
– Hon’ble Justice M.R. Shah, Mukesh Singh v. State, [SLP (Criminal) Diary No. 39528 of 2018].
The fact – the informant was the investigator, may not by itself vitiate the investigation as unfair or biased [Mukesh Singh v. State, (2020) 10 SCC 120]. Also, it is not always necessary, evidence of police witnesses have to be corroborated by independent witnesses [Dharampal Singh v. State of Punjab, (2010) 9 SCC 608 and Mukesh Singh]
– Hon’ble Justice V. Ramasubramanian, Sanjeet Kumar Singh v. State of Chhattisgarh, [Criminal Appeal No. 871 of 2021] decided on 30.08.2022.