First information report is a report relating to the commission. of an offence given to the police and recorded by it under s. 154, Cr. P.C.
As observed by the Privy Council in H.E. v. Khwaja, the receipt and recording of information report by the police is not a condition precedent to the setting in motion of a criminal investigation. Nor does the statute provide that such information report can only be made by an eye witness. First information report under s. 154 is not even considered a substantive piece of evidence. It can only be used to corroborate or contradict the informant’s evidence in court. But this information when recorded is the basis of the case set up by the informant.
It is very useful if recorded before there is time and opportunity to embellish or before the informant’s memory fades. Undue or unreasonable delay in lodging the F.I.R., therefore, inevitably gives rise to suspicion which puts the court on guard to look for the possible motive and the explanation for the delay and consider its effect on the trustworthiness or otherwise of the prosecution version.
In Apren Joseph v. State of Kerala (1972), the supreme court had the opinion that,
“No duration of time in the abstract can be fixed as reasonably for giving information of a crime to the police, the question of reasonable time being a matter for determination by the court in each case. Mere delay in lodging the first information report with the police is, therefore, not necessarily, as a matter of law, fatal to the prosecution. The effect of delay in doing so in the light of the plausibility of the explanation for the coming for such delay accordingly must fall for consideration on all the facts and circumstances of a given case.”
While talking on the delay in lodging FIR, the court said in the case,
“The mere fact that the eye witnesses did not gather up enough courage to go to the police station to lodge the first information report or to the place of the occurrence during the night or early in the following morning to give some aid to the deceased, who undoubtedly was no blood-relation of any one of the witnesses, does not show that they had not witnessed the occurrence and the whole story is imaginary and made up only for falsely implicating the accused due to enmity.”
  8 S.C.R. 133