The expression “reason to suspect” as occurring in Section 157(1) is not qualified as in Section 41(a) and (g) of the Code, wherein the expression, “reasonable suspicion” is used. therefore, it has become imperative to find out the meaning of the words “reason to suspect” which words are apparently clear, plain and unambiguous. Considering the context and the object of the procedural provision in question, we are of the view that only the plain meaning rule is to be adopted so as to avoid any hardship or absurdity resulting therefrom and the words are used and also to be understood only in common parlance. We may, in this behalf, refer to a decision of the Privy Council in AIR 1939 47 (Privy Council) wherein Lord Atkin said as follows:
When the meaning of the words is plain, it is not the duty of Courts to busy themselves with supposed intentions…. It, therefore, appears inadmissible to consider the advantages or disadvantages of applying the plain meaning whether in the interests of the prosecution or accused.
The word ‘Suspect’ is lexically defined in Webster’s Third International Dictionary as follows:
Suspect-to look up at, suspect; the act of suspecting or the condition of being suspected… to have doubts of; be dubious or suspicions about; (2) to imagine (one) to be guilty or culpable on slight evidence or without proof… (3) to imagine to be or be true, likely or probable: have a suspicion, intimation or inkling of.
In Corpus Juris Seconded (Vol. 83) at page 923 the meaning of the word ‘Suspect’ is given thus:
The term ‘suspect’, which is not technical, is defined as meaning to imagine to exist; have some, although insufficient, grounds for inferring; also to have a vague notion of the existence of, without adequate proof; mistrust; surmise. It has been distinguished from belief.
46. In the same volume, the expression “suspicion” is defined at page 927 as follows:
The act of suspecting or the state of being suspected; the imagination, generally of something ill; the imagination of the existence of something without proof, or upon very slight evidence, or upon no evidence at all….
In words and Phrases (Permanent Edition 40A) at page 590, the word ‘suspicion’ is defined thus:
Suspicion’ implies a belief or opinion as to guilt, based on facts or circumstances which do not amount to proof. Scaffido v. State 254 N.W. 651. The state of mind which in a reasonable man would lead to inquiry is called mere ‘suspicion’. Stuart v. Farmers’, Bank of Cuba City 117 N.W. 820.
Again at page 591 the said word is expounded as follows:
The word ‘suspicion’ is defined as being the imagination of the existence of something without proof, or upon very slight evidence, or upon no evidence at all. Cook v. Singer Sewing Mach. Co. 32 P. 2d 430, 431, 138 Cal. App. 418.
See also AIR 1946 123 (Privy Council) United States v. Cortez 66 L.Ed. 2d (US)(SCR)623 (II (A (3); and Dallison v. Caffery  2All E.R. 610.
One should not lose sight of the fact that Section 157(1) requires the police officer to have reason to suspect only with regard to the commission of an offence which he is empowered u/s 156 to investigate, but not with regard to the involvement of an accused in the crime. therefore, the expression “reason to suspect the commission of an offence” would mean the sagacity of rationally inferring the commission of a cognizable offence based on the specific articulate facts mentioned in the First Information Report as well in the Annexures, if any, enclosed and any attending circumstances which may not amount to proof. In other words, the meaning of the expression “reason to suspect” has to be governed and dictated by the facts and circumstances of each case and at that stage, the question of adequate proof of facts alleged in the first information report does not arise. In this connection, we would like to recall an observation of this Court made in the State of Gujarat Vs. Mohanlal Jitamalji Porwal and Another, while interpreting the expression ‘reasonable belief. It runs thus:
Whether or not the officer concerned had entertained reasonable belief under the circumstances is not a matter which can be placed under legal microscope, with an over-indulgent eye which sees no evil anywhere within the range of its eyesight. The circumstances have to be viewed from the experienced eye of the officer who is well equipped to interpret the suspicious circumstances and to form a reasonable belief in the light of the said circumstances.
See also Pukhraj v. D.R. Kohli  3 SCR 866.
Resultantly, the condition precedent to the commencement of the investigation u/s 157(1) of the Code is the existence of the reason to suspect the commission of a cognizable offence which has to be, prima facie disclosed by the allegations made in the first information laid before the police officer u/s 154(1).
In State of West Bengal and Ors. v. Swapan Kumar Guha and Ors. (albeit) Chandrachud, C.J. while agreeing with the judgment of Justice A.N. Sen with which judgment Justice Vardarajan also agreed, has expressed his view in his separate judgment on the above point under discussion as follows:
The position which emerges from these decisions and the other decisions which are discussed by brother A.N. Sen is that the condition precedent to the commencement of investigation u/s 157 of the Code is that the FIR must disclose, prima facie, that a cognizable offence has been committed. It is wrong to suppose that the police have an unfettered discretion to commence investigation u/s 157 of the Code. Their right of enquiry is conditioned by the existence of reason to suspect the commission of a cognizable offence and they cannot, reasonably, have reason so to suspect unless the F.I.R., prima facie, discloses the commission of such offence.
As pointed out in the earlier part of this judgment, Section 157(1) is qualified by a proviso which is in two parts (a) and (b). Clause (a) of the proviso is only an enabling provision with which we are not very much concerned. However, Clause (b) of the said proviso imposes a fetter on a police officer directing him not to investigate a case where it appears to him that there is no sufficient ground in entering on an investigation. As Clause (b) of the proviso permits the police officer to satisfy himself about the sufficiency of the ground even before entering on an investigation, it postulates that the police officer has to draw his satisfaction only on the materials which were placed before him at that stage, namely, the first information together with the documents, if any, enclosed. In other words, the police officer has to satisfy himself only on the allegations mentioned in the first information before he enters on an investigation as to whether those allegations do constitute a cognizable offence warranting an investigation.
From the above discussion, it is pellucid that the commencement of investigation by a police officer is subject to two conditions, firstly, the police officer should have reason to suspect the commission of a cognizable offence as required by Section 157(1) and secondly, the police officer should subjectively satisfy himself as to whether there is sufficient ground for entering on an investigation even before he starts an investigation into the facts and circumstances of the case as contemplated under Clause (b) of the proviso to Section 157(1) of the Code.