First Information Report

A First Information Report (FIR) is a written document prepared by police organizations in Bangladesh, India, and Pakistan when they receive information about the commission of a cognizable offence, or in Singapore when the police receives information about any criminal offence. It is generally a complaint lodged with the police by the victim of a cognizable offense or by someone on his or her behalf, but anyone can make such a report either orally or in writing to the police.

For a non cognizable offense a Community Service Register is created & registered.

FIR is an important document because it sets the process of criminal justice in motion. It is only after the FIR is registered in the police station that the police take up investigation of the case. Anyone who knows about the commission of a cognizable offence, including police officers, can file an FIR.

As described in law,

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Wikipedia