Something is rotten in corners of police departments across America. An environment that condones abusing suspects and treating citizens with disrespect has laid the foundation for police-involved brutality.

The tragic deaths of Freddie Gray in Baltimore, Eric Garner in New York and Walter Scott in Charleston, to name a few, have brought allegations of police misconduct into the national spotlight again. Any hope of rebuilding trust in the thousands of excellent officers who deserve community support lies in reforming the worst elements of police culture.

Racism is one of those elements. A U.S. Department of Justice study of the Ferguson (Mo.) Police Department found racial bias and profiling by officers in a city in which two-thirds of the population is black. Although the Justice Department decided not to file charges after white Ferguson officer Darren Wilson fatally shot Michael Brown, who was black and unarmed, the case highlighted police-community tension across the country.

In Baltimore, three of the six officers charged in the death of Freddie Gray are cops of color. All six of those officers are innocent until proven otherwise and deserve their day in court. Yet news reports that have surfaced since Gray's death have illuminated why so many Baltimore residents have lost faith in the cops. In that city and others, there have been too many "rough rides" in police vans and too many cases in which police have failed to provide medical help for suspects.

Some departments have taken reform seriously and produced results. Following a Justice Department review, for example, the Cincinnati Police Department significantly reduced use-of-force incidents and increased citizen satisfaction with police, according to a case study published in the Columbia Journal of Law. Justice Department intervention helped change the department's culture from a "militaristic model to one emphasizing problem solving and community interaction,'' the study concluded.

Based on a recent survey, the Police Executive Research Forum reported that the typical police cadet receives about 58 hours of gun training and 49 hours on defensive tactics. By comparison, cadets spend just eight hours learning to calm situations.

Chuck Wexler, a former assistant to the Boston Police Department and director of the research group, said police have "lost the confidence of the American people." To help rebuild it, his group is meeting with scores of police leaders in Washington, D.C., this week to call for a new era of training that focuses on defusing tense situations.

Recruiting is also key. Some studies suggest that college-educated and female officers are less likely to be involved in violent confrontations. Rank-and-file officers should support each other in self-policing, too. The majority of police officers who bring honor to their profession are made less safe and less effective when bad cops are in the ranks.

Those officers who behave as badly as the violent criminals they pursue must go. Their presence is a rot in law enforcement culture that must be removed.