Some years ago, elements of the Miami Police Department, acting on a drug tipoff, raided the wrong house and ended up firing more than 70 bullets into a 70-something-year-old black man while his granddaughter cowered in their bathtub.

A few years later, a Miami police officer shot and killed a young black man at point-blank range in a video arcade.

A few years after that, another Miami police officer stepped out onto the street and shot and killed a young black man approaching on a motorcycle.

 More recently, elements in the same police force shot and killed nine young black men within less than a year and many in highly questionable circumstances.

And those are the better publicized incidents in which police officers in this department, especially Hispanic officers, have killed young black men with impunity, with little evidence that the officers’ lives were in immediate danger.

Ask around and most black Miamians will tell you they are convinced that officers seem to be carrying out extra-judicial execution to take out the supposedly bad guys.

And now comes the U.S. Justice Department with the surreal announcement that it is launching an investigation into “whether there are systemic deficiencies that result in patterns or practices of unlawful conduct.” That is how Assistant Attorney General Thomas E. Perez astonishingly put it in a recent press conference in Miami.

Are they kidding?

There have been “systemic deficiencies” in the Miami Police Department for decades and there is no evidence that concrete steps have been taken to fix them.

Of course, not all Miami police officers are bad. Indeed, the problem seems more one of policies and procedures and of appallingly deficient leadership by the force’s command staff and the elected city officials.

The Justice Department investigation will turn out to be just a sham if all it does is take a year or more and come up with a conclusion that yes, indeed, there are “systemic deficiencies” in the Miami police force.

A serious approach is needed for a serious, highly troubling problem and that has not been forthcoming in almost a generation. The community demands more.