The Cleveland report was released a day after a Staten Island grand jury declined to indict a white New York City police officer in the choking death of an unarmed black man, Eric Garner, 43, and nearly two weeks after a grand jury in Missouri decided not to indict a white police officer who fatally shot an unarmed black teenager, Michael Brown. Both decisions led to demonstrations around the country, including violent protests in Missouri.

The report also came as law enforcement officials in other cities were grappling with police shootings. In Los Angeles, the police chief ruled on Wednesday that three officers accused of improper force in the fatal shooting of an unarmed man during a car chase last year had violated department rules, determining that most of the evidence did not support the officers’ claim that a “deadly threat” was present. And a grand jury in South Carolina returned a murder indictment this week against a former police chief of Eutawville in the 2011 killing of an unarmed black man he was trying to arrest.

Protests over the Garner case erupted again Thursday across the country, disrupting traffic and blocking streets in several cities, including New York, Boston, Chicago and Washington.

In the wake of the protests in Ferguson, President Obama on Monday met with civil rights leaders and law enforcement officials at the White House, citing a “simmering distrust that exists between too many police departments and too many communities of color.” Afterward, the president announced plans to provide money for police officers to wear body cameras, tighten standards on providing military-style equipment to local police departments and form a task force to study ways to improve local policing.

As a result of the federal investigation in Cleveland, the city has agreed to work toward a settlement with the Justice Department, known as a consent decree, that will overhaul practices, tighten policies on the use of force and subject the police to oversight by an independent monitor. Consent decrees in other cities, including Albuquerque, Detroit, New Orleans and Seattle, were put into effect after investigations into questionable police violence and other abusive practices. In Mr. Holder’s first five years in office, the Justice Department opened 20 civil rights investigations into police departments, more than twice the number in the five years before.