 According to Dotson, his officers were less active in enforcing the law because they were afraid they might be charged with breaking the law.FBI Director James Comey suggested that the Black Lives Matter movement is partly leading to a national rise in crime rates because police officers have pulled back from doing their jobs.A study published by the Justice Department said there was an increase in homicides in 56 large cities over the course of 2015, and examined the "Ferguson effect" as one of three plausible explanations.