Every time a person is killed by a police officer,
1. If a complaint is made, an FIR must be registered. Judicial precedence is clear that police do not have a discretion not to register an FIR. The FIR’s sincerity, veracity etc cannot be determined at the registration stage. Also, it is not necessary for the FIR to name the officers involved.
2. Once an FIR is registered, an investigation must be launched. The investigation may conclude that (a) no killing took place, or (b) that the killing was excused as an exercise of one’s right to private defense, or (c) that the killing was not excused and therefore illegal.
3. The Judicial Magistrate is not bound to agree with an investigation report which concludes that the killing took place in course of the exercise of the right to private defense. The judicial discretion must be exercised independently and if the Magistrate thinks that this is not conclusively proven, she can take cognizance under section 190 fo the Code of Criminal Procedure.

This blog has discussed the case in detail previously at this link.

One hopes that the Supreme Court will uphold the very sensible judgment of the AP High Court that an unnatural death needs to be investigated. Indeed, several other jurisdictions, including those with a far more conservative tradition of judicial interpretation of constitutional rights, have held that the right to life includes a duty on the state to investigate unnatural deaths (see the European Court of Human Rights jurisprudence on the duty to investigate, for example). 

Overturning the AP ruling will be against the core values of liberal democracy.

UPDATE:  The case has been referred to a larger Bench. The latest order is here.