(CNN)Early Thursday -- during the ongoing protests that continue to shake Ferguson, Missouri -- two police officers were shot. Such violence and lawlessness should never be tolerated. But the unrest during which it occurred demonstrates that the people of Ferguson have lost all confidence in their police department. And the resignation of the police chief this week won't be enough to restore faith in law and order. Everyone in the department needs to step down so the department can be rebuilt from the ground up. It is easy to see why. After a police officer shot Michael Brown, the U.S. Department of Justice conducted an investigation into the Ferguson Police Department. What investigators found was a "pattern and practice" of discrimination against African-Americans. In a town with a black population of 67%, black people represented 85% of vehicle searches, 90% of the traffic violations and 93% of the arrests. There is no way to justify this. Now, the Department of Justice has an opportunity to gut the Ferguson Police Department and rebuild it from scratch. In fact, it's more than an opportunity: It's a necessity. In the court of law, there is an old closing argument that goes like this: You sit down, pour yourself a bowl of stew and find that the first piece of meat that you taste is rancid. You don't put just that piece aside; you throw out the whole bowl. Lawyers use this story to say that if you catch a witness lying about one thing, then you can't believe anything they say. Unfortunately, it is an analogy that can be applied to the Ferguson Police Department. The Department of Justice report revealing unquestionable racist bias that permeated the entire department cannot be ignored, and the problems it reveals cannot be fixed from the inside. If there are a few good cops in the Ferguson Police Department, they need to leave, and they need to go elsewhere to continue their proud law enforcement career without being overshadowed by their involvement in a poisoned organization. In fact, everyone in the Ferguson Police Department needs to leave, from the top to the bottom. The police department should be completely reconstituted under Department of Justice control in a manner that ensures that citizens of Ferguson receive the type of public service they pay for and deserve -- and more importantly, in a manner that protects their rights, not only as citizens of Ferguson, Missouri, but as constitutionally protected citizens of our country. A completely rebuilt Ferguson Police Department, established with a charter to enforce the law with equality, could serve as an example for every law enforcement agency in the country. A new Ferguson Police Department could show what a concerted, roots-up effort toward nonracist behavior in a police department can be. Under Justice Department leadership, the Ferguson Police Department could become a model for practices such as equipping all police with body cameras, community policing and better use of force training. If we can create from the ashes of the Ferguson Police Department a model that works, it may provide some consolation for minorities who have been disproportionately targeted by law enforcement. And if the black community in Ferguson -- in fact, people of every race in Ferguson -- can look back five years from now and see an unbiased organization of public servants who give respect and get respect, who reduce fear rather than cause it, then perhaps the tragedy of Michael Brown's death will stand for something.
Mark O'Mara: Justice Department says Ferguson has record of racial discrimination . O'Mara says police force in Ferguson must be dismantled . He says a new department, with new practices to prevent replay of abuses, can be model for others, help repair injustices in Ferguson .