[Young Scholar]

What's the point of being undercover if they're going to break down a door (and do anything in which they need to be known as police)? It seems as though they deserve the blame, not only for breaking into the wrong house (which could be excusable), but for failing to make it clear that they were police officers, thereby making the shooting far more likely.

[Hazcat]

I know if some one broke down my door and just started yelling POLICE (I'll assume they did) they better duck!

[Enterprise]

I guess it depends on the agency. Some agencies require that a uniformed officer be present when undercover teams serves search warrants. Even then, mistakes happen.

[Churchillspirit]

Perhaps the old lady was a little deaf and didn't hear them identify themselves as police.

Sad story.