All to often, you are correct. Here in Florida, twice last year. police illegally entered homes without a knock, the home owner, not knowing they were police, defended himself and was killed.Cops will generally get away with shooting people.
Much like this situation...you will just never know what really happened.
If you rob a bank and the police kill 5 people chasing and shooting at you...
You now have 5 shinny new first degree murder charges to add to your bank robbery.
Even though the police committed felonies for illegally entering a house, they were not charged in the two deaths.
Now, the most the family can do is sue the local government for wrongful death but Florida law restricts this claim to $100,000. This limit was set decades ago when $100,000 was considered a lot of money but today it is not and not enough incentive for local governments to change their ways.