4th amendment had nothing to do with the case

The LA sheriffs enter a home  and shoot a law abiding citizen.   

The Los Angeles County Sheriff's Department received word from a confidential informant that a potentially armed and dangerous parolee-at-large had been seen at a certain residence. While other officers searched the main house, Deputies Conley and Pederson searched the back of the property where, unbeknownst to the deputies, respondents Mendez and Garcia were napping inside a shack where they lived. Without a search warrant and without announcing their presence, the deputies opened the door of the shack. Mendez rose from the bed, holding a BB gun that he used to kill pests. Deputy Conley yelled, "Gun!" and the deputies immediately opened fire, shooting Mendez and Garcia multiple times. Officers did not find the parolee in the shack or elsewhere on the property.

This is reckless endangerment, a mal-practice subject to lawsuit, or involuntary manslaughter.  

If law enforcement officers make a "seizure" of a person using force that is judged to be reasonable based on a consideration of the circumstances relevant to that determination, may the officers nevertheless be held liable for injuries caused by the seizure on the ground that they committed a separate Fourth Amendment violation that contributed to their need to use force? The Ninth Circuit has adopted a "provocation rule" that imposes liability in such a situation.

Even if they had a valid search warrant or probable cause, they engaged in reckless behavior by not announcing their presence nor following police procedure.  They are subject to a civil lawsuit, or criminal complaint for involuntary manslaughter.  This is no different than a doctor removing the heart, thinking it was the liver.

The lawyer who brought the case is dumber than molasses.

Let us go back to auto accidents.  The cop in his car, gets an emergency call, turns on the siren, looks, and takes off; hits and kills another driver.  This is part of the job, the cop did everything right.

Now the cop gets an emergency call, guns the engine, takes off but does not get the siren going in time, hits and kills.  He is liable.

Cops, like any other citizen, can be busted for reckless endangerment leading to death, injury or property damage. Reckless endangerment means obviously doing the job dengerously and outside of standard procedure.