Attorney General Eric Holder announced Thursday that "there is reasonable cause to believe that the Cleveland Division of Police engages in a pattern and practice of using excessive force," after Justice Department investigators examined nearly 600 cases of use of force that occurred between 2010 and 2013. 
 
 Holder went on to say that Cleveland and the Justice Department had agreed on a statement of principles that will lead to a consent decree. 
 
 The investigation in the Cleveland Police Department was launched in March 2013, "following a number of high profile use of force incidents and requests from the community and local government to investigate the [police department]," the report released Thursday said. 
 
 The report cited specific incidents, including a January 2011 police chase of an unarmed man, who suffered "kicks to the head" after he had "surrendered to officers and was handcuffed and prone on the ground." None of the officers filed a report on the use of force, and none "were appropriately disciplined for failing to report the use of force." 
 
 In another incident from November 2012, the report said, "over 100 Cleveland police officers engaged in a high speed chase, in violation of [Cleveland Division of Police] policies, and fatally shot two unarmed civilians. [Cleveland Division of Police] officers ultimately fired 137 shots at the car, killing both its occupants." 
 
 The unreasonable practices the Justice Department found included the following: 
 
 Unnecessary and excessive use of deadly force, including shootings and head strikes with impact weapons 
 
 Unnecessary, excessive or retaliatory use of less lethal force including Tasers, chemical spray and fists 
 
 Excessive force against persons who are mentally ill or in crisis, including in cases where the officers were called exclusively for a welfare check 
 
 Employment of poor and dangerous tactics that places officers in situations where avoidable force becomes inevitable 
 
 Justice Department investigators also said the division doesn't adequately review and investigate the use of force by its officers or fully investigate misconduct allegations or identify and respond to patterns of at-risk behavior. 
 
 The Justice Department and Cleveland Police Department so far have only agreed to come to an agreement about how to address this problem. They will work out the details of that agreement -- the so-called "consent decree" -- in the coming months, but it will include a requirement for an independent monitor who will oversee necessary reforms. 
 
 Holder invoked the names of Michael Brown, Eric Garner and 12-year-old Tamir Rice, who was killed in Cleveland in November, noting that there are ongoing federal civil rights investigations for each of those incidents. The Justice Department's investigation predates the recent shooting of Rice, and CBS News has learned that while that incident was not taken into consideration in the investigation, it will be considered as an agreement on changes that must be made within the Cleveland Division of Police. 
 
 "The tragic losses of these and far too many other Americans - including, just last month, the shooting death of 12-year-old Tamir Rice here in Cleveland - have raised urgent, national questions. And they have sparked an important conversation about the sense of trust that must exist between law enforcement and the communities they serve and protect." 
 
 The Cleveland investigation is the same kind of investigation the Justice Department launched into the Ferguson Police Department after one of its officers, Darren Wilson, shot and killed Michael Brown, an unarmed 18-year-old. 
 
 Holder made his announcement in Cleveland, where he is hosting a round table discussion as part of a tour of several U.S. cities where he will meet with local leaders and discuss relations between the community and law enforcement. He is also expected to visit Memphis, Chicago, Philadelphia, and Oakland in the coming weeks. ||||| Play Facebook 
 
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 An independent monitor will oversee changes in the Cleveland police department after a federal investigation found a pattern of “unreasonable and in some cases unnecessary force.” 
 
 The agreement, announced Thursday by outgoing Attorney General Eric Holder, follows a civil rights investigation launched last year, well before the police shooting death two weeks ago of Tamir Rice, a 12-year-old boy who was carrying a pellet gun. 
 
 Federal investigators found that the pattern of improper police tactics included shootings, blows to the head and excessive force against the mentally ill. Investigators concluded that Cleveland officers are not given adequate training and supervision. 
 
 Among the high-profile episodes that led to the investigation was a police shooting of an unarmed man and woman in November 2012 that followed a high-speed chase. Thirteen officers fired 137 shots at the man and woman. One officer and six supervisors were indicted. 
 
 While the investigation began before the 12-year-old was killed, Holder mentioned it as among a series of police killings that have started what he called an urgent national conversation about relations between police and citizens. 
 
 President Barack Obama, speaking at an education summit in Washington on Thursday, mentioned another incident — the chokehold death of Eric Garner, a New York man who was confronted by police in July for allegedly selling individual cigarettes. A grand jury declined to indict the officer. 
 
 “When it comes, unfortunately, as we’ve seen in recent days, to our criminal justice system,” Obama said, “too many Americans feel deep unfairness when it comes to the gap between our professed ideals and how laws are applied on a day-to-day basis.” 
 
 Duane Deskins, the first assistant prosecutor of Cuyahoga County, said the goal in Cleveland would be “a more transparent and effective system of justice.” 
 
 “I think every city in every community has its own set of particular issues,” he said. “I think we are trying to solve the problems that we have here.” 
 
 IN-DEPTH 
 
 — Pete Williams and Erin McClam with Ty Wright ||||| FILE- In this Dec. 3, 2014 file photo, Pastor Henry Currie of Mary B. Wise Baptist Church collects himself during services for Tamir Rice, in Willoughby, Ohio. Rice, 12, was shot and killed by a Cleveland... (Associated Press) 
 
 FILE - In this Dec. 4, 2014, file photo, protesters carry signs criticizing the police, and replicas of coffins during a march over the Brooklyn Bridge to protest a grand jury's decision not to indict... (Associated Press) 
 
 FILE- In this Nov. 25, 2014 file photo, demonstrator Maryam Said raises her painted hands during a protest against a grand jury's decision on Monday not to indict Ferguson police officer Darren Wilson... (Associated Press) 
 
 FILE- In this July 23, 2014 file photo, mourners gather during a funeral service for Eric Garner at Bethel Baptist Church in the Brooklyn borough of New York. A grand jury ruled not to indict the police... (Associated Press) 
 
 FILE- In this Nov. 25, 2014 photo, a man spray-paints protest graffiti in Oakland, Calif., a day after the announcement that a grand jury had decided not to indict Ferguson, Mo., police officer Darren... (Associated Press) 
 
 FILE - In this Aug. 25, 2014 file photo the casket containing the body of Michael Brown is surrounded people gathered to say goodbye as it leaves Friendly Temple Missionary Baptist Church in St. Louis.... (Associated Press) 
 
 FILE- In this Dec. 5, 2014, file photo, mourners surround the casket of 28-year-old Akai Gurley during his wake at Brown Memorial Baptist Church in New York. A New York City Police officer shot Gurley... (Associated Press) 
 
 FILE- In this Dec. 3, 2014 file photo, people participate in a protest in response to the grand jury's decision in the Eric Garner case in Times Square in New York. A grand jury cleared the white New... (Associated Press) 
 
 In each place, individuals — all unarmed except for a child carrying a pellet gun — died at the hands of police officers. All of the dead were black. The officers involved, white. 
 
 To many Americans, it feels like a national tidal wave. And yet, no firm statistics can say whether this spate of officer-involved deaths is a growing trend or simply a series of coincidences generating a deafening buzz in news reports and social media. 
 
 "We have a huge scandal in that we don't have an accurate count of the number of people who die in police custody," says Samuel Walker, emeritus professor of criminal justice at the University of Nebraska at Omaha and a leading scholar on policing and civil liberties. "That's outrageous." 
 
 There are some raw numbers, but they're of limited value. 
 
 The FBI's Uniform Crime Reports, for instance, track justifiable police homicides — there were 1,688 between 2010 and 2013 — but the statistics rely on voluntary reporting by local law enforcement agencies and are incomplete. Circumstances of the deaths, and other information such as age and race, also aren't required. 
 
 The Wall Street Journal, detailing its own examination of officer-involved deaths at 105 of the nation's 110 largest police departments, reported last week that federal data failed to include or mislabeled hundreds of fatal police encounters. 
 
 Put simply: It's hard to know for certain what is happening on the ground. 
 
 "We want a comprehensive picture ... so people can be aware of what really goes on, and not the claptrap put out by people with agendas," says David Klinger, a professor of criminology at the University of Missouri-St. Louis who has studied use of deadly force and hopes to get funding for a pilot project that could provide better national statistics. 
 
 To those who have taken to the streets to protest in recent weeks, that lack of context is almost beside the point. 
 
 "These are communities that have been living for generations under the yoke of what has felt like an occupying force," says Phillip Atiba Goff, co-founder of UCLA's Center for Policing Equity. "And regardless of what any of the stats are ever going to say, if we don't address the reality of that experience, then we're shooting ourselves in the foot in our attempts to make good on our promise of democratic principles." 
 
 The high-profile cases have erupted one after the other. 
 
 On July 17, 43-year-old Eric Garner died after officers tried to arrest him on suspicion of selling untaxed cigarettes on a New York City street. Cellphone video captured the scene as one officer wrapped his arm around Garner's neck, and the black man repeatedly pleaded, "I can't breathe." 
 
 Tensions escalated on Aug. 9, when Officer Darren Wilson fatally shot unarmed, 18-year-old Michael Brown in the St. Louis suburb of Ferguson. 
 
 On Nov. 22, a Cleveland officer shot and killed 12-year-old Tamir Rice after responding to reports of an armed man at a city park. Rice had been holding a pellet gun. 
 
 Two days later, officials announced that a grand jury had declined to return an indictment in the Brown case. Fires from the resulting protests in Ferguson had barely stopped smoldering when word came there would be no charges against the officer in New York City. Again, angry protesters marched. 
 
 Then a grand jury in Orangeburg County, South Carolina, returned a murder indictment Wednesday against a former small-town police chief in the May 2011 shooting death of an unarmed black man. 
 
 Richard Combs, who was the sole officer for the town of Eutawville, had been charged with official misconduct for shooting Bernard Bailey, who had come to the town hall to argue about a ticket his daughter had received. Combs' attorney questioned prosecutor David Pascoe's motives in seeking the murder charge. 
 
 "He's trying to make it racial, because his timing is perfect," John O'Leary said. "He's got all the national issues going on, so they want to drag him (Combs) in and say, 'Look what a great community we are here, because we're going to put a police officer who was doing his job in jail for 30 years.' That's wrong." 
 
 Walker, co-author of the book "The Color of Justice: Race, Ethnicity, and Crime in America," says much of the anger out there comes from years of conflict between the black community and law enforcement. 
 
 "Within the African-American community, there has been an experience of disrespect, offensive language, mistreatment in terms of stops and so on," he says. "And there's a sense that the police are out to get them." 
 
 It's not just the killings that have minority communities "fed up," says Inimai Chettiar of the New York University law school's Brennan Center for Justice. 
 
 "African-American communities are tired of being over-policed, over-prosecuted, sent to prison, having men taken away from their communities, having families broken," says Chettiar, director of the center's Justice Program. "I think there's much more than just an instinctual sense that there is something amiss in these communities. I think people are tired of 'tough on crime.'" 
 
 Whether such incidents are on the rise, says Walker, "we're certainly more aware. And, certainly, the digital revolution has had a huge impact." 
 
 Goff compares it to the ice bucket challenge phenomenon of this past summer — in which a series of viral videos raised millions of dollars for research into amyotrophic lateral sclerosis, or Lou Gehrig's Disease. 
 
 "Once something is trending, so that it's in the American consciousness, people become aware of it," he says. "The reason we're hearing about this is because we're hearing about it. It has its own momentum." 
 
 Goff has begun work on creating a policing database, with funding from the Department of Justice, the National Science Foundation and private groups. He says it would include not just deaths but all police stops and uses of force. 
 
 "Is it getting better? Is it getting worse? What are the actual numbers?" asks Goff. "You know, when a plane crashes, it feels all of a sudden like it's not safe to fly. But if you look at the statistics, it's way safer to fly — and always has been — than to drive a car." 
 
 The Department of Justice is investigating possible federal civil rights violations in the Ferguson case and has opened an investigation into Garner's death in New York. On Thursday, the agency reached an agreement to reform the Cleveland Police Department after concluding that officers there use excessive and unnecessary force far too often — an investigation prompted in part by the deaths of the two black occupants of a car involved in a high-speed chase. In that case, 13 officers fired 137 shots at the unarmed suspects. 
 
 Chettiar is hopeful that recent events will create the "political and public will" to begin gathering and analyzing the facts. 
 
 "In addition to personal stories," she says, "statistics help people change their minds." 
 
 ___ 
 
 AP writers David Crary in New York and Meg Kinnard in Orangeburg, South Carolina, contributed to this story.
– Cleveland police use unnecessary force so often that the department must let an independent monitor make sure reforms are put into place, reports NBC News. That's one result of a Justice Department investigation of 600 incidents between 2010 and 2013 that faults the department for poor training and a "pattern and practice of using excessive force." The investigation began well before the recent police shooting of 12-year-old Tamir Rice at a city recreation center, and it's the same kind of federal investigation now underway in Ferguson, Missouri, notes CBS News. "We saw too many incidents in which officers accidentally shot someone either because they fired their guns accidentally or because they shot the wrong person," says the report. In one incident, officers fired 137 shots at a car with two unarmed civilians inside who were fleeing police. Both were killed. In another, officers kicked and punched a man who was restrained and on his stomach, reports AP. He was hospitalized for a broken bone near his eye. (The officer in the Eric Garner case maintains that his chokehold was a wrestling move learned at the police academy.)