( CNN ) In late January , Kristiana Coignard , a seventeen-year-old woman with bipolar disorder and depression , walked into the police department in Longwood , Texas , with `` I have a gun '' written on her hand . She also had a knife in her waistband . Officer Glenn Derr approached her , read her message , and quickly restrained her . He then let her go , restrained her on the floor , then let her go again as two other officers entered the scene . On the surveillance video that the department released , you can see the moment in which Coignard decides to die . She raises her knife and charged at Derr , who shoots , as does one of the other officers . The third officer deploys a TASER , but by then it was too late . She lies on the floor for a few minutes until emergency medical services arrive . The department has released a statement and held a press conference . The officers have been placed on administrative leave pending the outcome of an investigation by the Texas Rangers . When police misread the circumstances of encounter with an individual with mental health crisis , the possibility for violence rapidly escalates . The only solution is for law enforcement to try to stabilize every encounter , to the extent possible , as if it involved psychiatric disability . As a nation , we are in the midst of an extended conversation about police violence , and this case stands out as unusual . The victim was white and female , for one thing . Moreover , ugly use-of-force incidents usually result from police being too quick to escalate , rather than too slow . In the last few years I 've watched many videos , either from cell phones or police cameras , and read even more incident reports describing encounters between law enforcement and people with psychiatric disabilities . I can not recall seeing a case in which an officer has a potentially violent individual so well subdued , and then just backs away . I wondered if just as being black and male sparks some officers to be overly aggressive , a confrontation with a slender white female might produce the opposite effect . The best known victims of police violence while in mental health crisis are black men . Police arguably are more prone to consider black men dangerous . They demand instant compliance and respond to any hesitation as a threat . For example , in cases such as the death of Kajieme Powell in St. Louis , or Dontre Hamilton in Milwaukee , police officers engaged aggressively , demanding the individual act in a non-disabled manner and comply . In my review of such encounters , I 've argued that Powell , Hamilton , and many other individuals in similar circumstances , could n't follow orders as expected . Therefore , they were shot and killed . These are cases of law enforcement officers failing to recognize the complexity of a mental health situation . In Longview , Texas , on the other hand , the incident shows the other side of the coin -- under aggression . I spoke to Lou Hayes , a police officer and a trainer for use-of-force incidents , he said that in his experience many officers are likely to be less aggressive toward women , especially small women , in ways that put everyone in greater danger . `` Generally speaking , male officers are more reluctant to use lawful , justified , and necessary levels of force against women as compared to incidents with men . '' He also said that use-of-force models for a suspect armed with a knife , but restrained , might differ . Hypothetically , Hayes says that if he could control a suspect 's arms , he would not let her free from the restraint hold , but that if he feared he might lose control , backing up and readying his firearm might be a reasonable choice . At this time Officer Derr is not speaking about his decision-making , due to the ongoing investigation , so I do n't know why he did n't try to handcuff her . I expect the investigation to determine that he was operating within the norms of his training for use-of-force . There 's no question that using a firearm and aiming for center mass is the correct response for someone at close proximity charging you with a butcher knife raised . It 's just not the only way to handle these situations . For example , in Milwaukee recently , a man with a butcher knife charged at police officers . They held their fire , remembering the death of Dontre Hamilton , and instead led him in a chase around parked cars , shouting at him to drop his knife , and simply waited until he eventually complied . That 's a model of tactical restraint that we need to see applied more broadly . Encounters between people with psychiatric disabilities and law enforcement can be dangerous . Studies estimate that around half the people killed by law enforcement every year have psychiatric disabilities such as schizophrenia or bipolar disorder . There will always be some situations in which the threat level is so great that there 's no way to stabilize it peacefully . But the death of Kristiana Coignard was not one of them . Her death demonstrates that the ongoing crisis of violent police encounters with people with mental health transcends race , class and gender . It requires fundamental rethinking of strategic approaches to these types of incidents on a national level . Until that happens , the unnecessary deaths will continue .
Kristiana Coignard , who had mental illness , was killed after she raised knife and charged at police . David Perry : Encounters between people with psychiatric disabilities and law enforcement can be dangerous .