One out of every four police shooting victims has a severe mental illness. That lesson was echoed this holiday season when Chicago police encountered 19-year-old Quintonio LeGrier in the midst of an “emotional problem” and shot him dead, allegedly without warning, according to a lawsuit filed by the teen’s father.

“By all accounts—official and unofficial—a minimum of one in four fatal police encounters ends the life of an individual with severe mental illness,” according to a report from the Treatment Advocacy Center, a Virginia-based nonprofit dedicated to eliminating barriers to the treatment of severe mental illness. “Given the prevalence of mental illness in police shootings, reducing encounters between on-duty law enforcement and individuals with the most severe psychiatric diseases may represent the single most immediate, practical strategy for reducing fatal police shootings in the United States.”

#CPD keeps emphasizing they ‘accidentally’ killed #BettieJones while providing no explanation as to why they killed #Quintonio on purpose.

— Ida’s Disciple (@prisonculture) December 27, 2015

“There are serious questions about yesterday’s shootings that must be answered in full by the Independent Police Review Authority’s investigation,” Emanuel said in a statement on Sunday. “It is clear changes are needed to how officers respond to mental health crises.”

And as many critics were quick to point out, Mayor Emanuel in 2012 closed six of the city’s 12 mental health clinics—largely in low-income, high-crime neighborhoods—without holding hearings or initiating a study or task force. Lacking the proper services or treatment, family members are left to call police when a loved one suffers from a mental episode. Faced with an overzealous criminal justice system, many mentally ill people wind up in Cook County Jail, which has been called America’s largest mental hospital, even in the words of its own top official, Cook County sheriff Tom Dart.