2) Once FIR is registered, within 24 hours copy is lodged before magistrate in court. So that no one can temper or change FIR. Police has to maintain a diary, in which he has to record every step taken pursuant to FIR.
3) Within 90 days, he has to complete investigation and he has to give report to court.The court has to take final call on report, if as per report court thinks that crime is made out, he can start trial.
4) If Police says, no crime is made out, then the judge may close FIR, or may order trial even if police says no case is made out. He has power to reject police reports.
5) In between these proceedings, anticipatory bail, bail, bail by police, remand, search and seizure, non bailable warrants, seizure of property of absconder, red corner notice for international accused, etc can happen.
6) If FIR is false, cross FIR can be filed, FIR for malicious prosecution can be filed, suit for damages can be filed. If FIR itself is abuse of criminal law, filed falsely, then High Court and Supreme Court has powers to set aside such FIR.