Kevin Johnson

USA TODAY

A federal review of policing in Cleveland found that officers' use of unreasonable force was part of a pattern of behavior that was in some cases endorsed by supervisors.

The Justice Department's scathing findings, disclosed Thursday as a wave of protests took aim at police conduct in Ferguson, Mo., and New York, were relayed to city officials in a 58-page summary of a 21-month investigation into policing operations.

Cleveland also has been the site of protests over last month's police shooting of a 12-year-old boy, who was in possession of a toy gun.

The officer identified as the shooter in the case reportedly displayed emotional problems and poor firearm skills in his former job with a neighboring law enforcement agency before joining the Cleveland force where he was a rookie officer at the time of last month's incident.

The Justice review examined 600 incidents in which police used some method of force between 2010 and 2013. It concluded in part that law enforcement is "sometimes chaotic and dangerous … and frequently deprives individuals of their constitutional rights.''

Among the most troubling disclosures:

• In addition to fatal shootings, the excessive force involved victims who were struck in the head, sometimes with the butts of police-issued firearms.

• Some of the incidents involved the mentally ill or emotionally disturbed in cases where officers were called merely to check on their welfare.

• Poor training contributed to cases in which policed employed dangerous tactics that placed the general public at risk.

"Determining whether a pattern or practice of the unreasonable use of force exists was not a close case,'' the report concluded.

Attorney General Eric Holder announced the findings in Cleveland, where federal authorities urged the appointment of a monitor as part of a tentative agreement to oversee needed reforms.

"We have determined that there is reasonable cause to believe that the Cleveland Division of Police engages in a pattern or practice of using excessive force,'' Holder said at a briefing where he was joined by Cleveland Mayor Frank Jackson.

Jackson was among a number of local leaders who had called for the federal review.

"Although we may have disagreements on some facts or conclusions drawn,'' Jackson said, "the city of Cleveland remains committed to continue making appropriate changes to the policies, procedures and training that guides the use of force by the division of police.''

The mayor did not elaborate on the nature of the "disagreements.''

The Justice examination, Holder said, had revealed "systemic deficiencies, including insufficient accountability, inadequate training and equipment, ineffective policies and inadequate engagement with the community.''

Holder also was in Cleveland as part of a six-city tour aimed at mending strained relations between the police and the communities they serve.

In addition to the community meetings, the administration has established a national task force to review law enforcement practices; established new standards for the distribution of surplus military equipment to police agencies; and pledged to help fund the distribution of 50,000 body-worn cameras to police departments as a guard against officer misconduct.

"We are committed to moving forward together, here in Cleveland and throughout the nation to spur renewed engagement, renewed trust and renewed momentum to translate coordinated action into meaningful results,'' Holder said.