Section 8 of Indian Evidence Act : Motive , preparation and previous or subsequent conduct : Any fact is relevant which shows or constitutes a motive , preparation for any act in issue or relevant facts.
The conduct of any party or of any agent to any party to any suit or proceeding in reference to such suit or proceeding or in reference to any fact in issue therein or relevant there to and the conduct of any person an offence against whom is the subject of any proceeding is relevant if such conduct influences or is influenced by any fact in issue or relevant fact and whether it was previous or subsequent there to.
Thus if motive , preparation or previous or subsequent conduct does not exist then there was no intention of person to do crime. Such factors must be saw to collect evidence as these factors will lead the case.
Once an arrest is made the prosecutor will investigate.
Any lack of evidence would be attributed to the state because they have the burden of proof and lack of evidence can create a reasonable doubt.
Absence or insufficiency of admissible evidence that the party bearing the burden of proof must provide to establish one or more essential elements of its case.
In instance of no evidence the opposing party may request the court to dismiss the case.