If the informant himself is the investigator, then by itself it cannot be said that the investigation is vitiated on the ground of bias: SC

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Mukesh Singh v State (Narcotic Branch of Delhi)

Special Leave Petition(Criminal) Diary No.39528/2018 decided on August 31, 2020.



BENCH- Arun Mishra, Indira Banerjee, Vineet Saran, MR Shah,Ravindra Bhat, JJ.



 The present appeal arises out of SLP filed by accused who challenged the Supreme Court decision in the case of Mohan Lal v State of Punjab (2018) 17 SCC 627 (hereinafter referred as ‘Mohan Lal Case’). In Mohan Lal case, the Hon’ble Supreme Court held that in case the investigation is conducted by the police officer who himself is the complainant, the trial is vitiated and the accused is entitled to acquittal. The same was challenged in case of Mukesh Singh v State and two judge’s bench of Supreme Court referred the matter to larger bench.



When an investigation is conducted under the Narcotic Drugs and Psychotropic Substances Act (hereinafter referred as ‘NDPS Act’) will it get vitiated if the informant and investigating officer are same?








The Counsel for appellant argued that free and fair trial is part of Article 21 of Constitution of India. The same is in consonance with the age-old principles of law that “Nemo debetessejudex in causa proporiasua

The Respondent argued that Cr.P.C. itself has provisions for vitiation and non-vitiation of trial and it does not have any such provisions  for investigating officer therefore proceeding should not be vitiated.


It was argued that officer or the raiding party which effects recovery are witnesses to the said fact and therefore investigation of the said aspect has to be carried out by an independent agency.


It was argued that irregularity in investigation would not lead to acquittal unless failure of justice is shown. Illustration (e) to Section 114 of the Indian Evidence Act which permits the Court to raise a presumption that official acts have been regularly performed was relied upon.




The Constitutional Bench of the Supreme Court overruling the three judges bench decision in case of Mohan Lal Case and held that if the informant himself is the investigator, then by that itself cannot be said that the investigation is vitiated on the ground of bias or the like factor. The question of bias or prejudice would depend upon the facts and circumstances of each case. Therefore, merely because the informant is the investigator, by that itself the investigation would not suffer the vice of unfairness or bias and therefore on the sole ground that informant is the investigator, the accused is not entitled to acquittal.

Furthermore, the Court said that only in a case where the accused is able to establish and prove the bias and/or unfair investigation by the informant-cum-investigator then he will be entitled to acquittal and not otherwise.



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