“21. In Sachchey Lal Tiwari v. State of U.P. [(2004) 11 SCC 410: 2004 SCC (Cri) Supp 105] this Court while considering the evidentiary value of the chance witness in a case of murder which had taken place in a street and a passerby had deposed that he had witnessed the incident, observed as under:
Supreme Court
If the offence is committed in a street only a passerby will be the witness. His evidence cannot be brushed aside lightly or viewed with suspicion on the ground that he was a mere chance witness. However, there must be an explanation for his presence there.
The Court further explained that the expression “chance witness” is borrowed from countries where every man’s home is considered his castle and everyone must have an explanation for his presence elsewhere or in another man’s castle. It is quite unsuitable an expression in a country like India where people are less formal and more casual, at any rate in the matter of explaining their presence.
22. The evidence of a chance witness requires a very cautious and close scrutiny and a chance witness must adequately explain his presence at the place of occurrence (Satbir v. Surat Singh [(1997) 4 SCC 192: 1997 SCC (Cri) 538], Harjinder Singh v. State of Punjab [(2004) 11 SCC 253: 2004 SCC (Cri) Supp 28], Acharaparambath Pradeepan v. State of Kerala [(2006) 13 SCC 643: (2008) 1 SCC (Cri) 241] and Sarvesh Narain Shukla v. Daroga Singh [(2007) 13 SCC 360: (2009) 1 SCC (Cri) 188]). Deposition of a chance witness whose presence at the place of incident remains doubtful should be discarded (vide Shankarlal v. State of Rajasthan [(2004) 10 SCC 632: 2005 SCC (Cri) 579]).
23. Conduct of the chance witness, subsequent to the incident may also be taken into consideration particularly as to whether he has informed anyone else in the village about the incident (vide Thangaiya v. State of T.N. [(2005) 9 SCC 650: 2005 SCC (Cri) 1284]). Gurcharan Singh (PW 18) met the informant Darshan Singh (PW 4) before lodging the FIR and the fact of conspiracy was not disclosed by Gurcharan Singh (PW 18) and Darshan Singh (PW 4). The fact of conspiracy has not been mentioned in the FIR. Hakam Singh, the other witness on this issue has not been examined by the prosecution. Thus, the High Court was justified in discarding the part of the prosecution case relating to conspiracy. However, in the fact situation of the present case, acquittal of the said two co-accused has no bearing, so far as the present appeal is concerned.”
Jarnail Singh vs. State of Punjab, (2009) 9 SCC 719