Policing experts who reconstructed the events of the day said that Baltimore police did not send enough officers to the situation at the start, failed to quickly make arrests once trouble began and did not deploy additional officers quickly enough. Key decisions led the situation to spiral out of control in a short 90 minutes, a lesson other police departments should heed…

Baltimore cops are trained to handle violent crowds, former police officials told TIME. Officers are drilled in maneuvers — how to form defensive lines, what formations to stand in, how to divide and conquer a crowd. But while police can practice arrests, subduing suspects and even home assaults, there is no real preparation for an angry mob like facing an angry mob itself. In the 90 minutes that Mondawmin Mall transformed from transit hub to launching pad for a riot, Baltimore police were outnumbered and too passive in pursuing arrests, experts said…

The officers at Mondawmin Mall were too small a group to properly handle the crowd, experts say. There were enough officers at the mall to hold a line and some property, but not enough to penetrate the crowd and make arrests, says Neill Franklin, who oversaw Baltimore police training from 2000 to 2004. “You’ve got to have enough boots on the ground,” said Franklin. “Without that, there’s nothing you can do. You’ll be overwhelmed very quickly.” Also important for policing is a deep familiarity with surrounding streets and alleys. In order to secure an area, Franklin said, police should know all the access and exit points where protestors can approach from.