Natasha McKenna (Courtesy of Natasha McKenna's family) (Courtesy of Natasha McKenna's family)

IT’S BEEN more than three months since a mentally ill woman, Natasha McKenna, died after she was shot four times with a Taser stun gun by a guard in the Fairfax County jail. Since her death on Feb. 8, county officials have offered repeated assurances that a full investigation is underway, and that the facts surrounding the guards’ struggle with Ms. McKenna — which was recorded in full on video — will be laid bare.

To date, however, it’s remarkable how little discernible progress authorities have made in providing an accounting of the circumstances leading to her death. A police investigation, hung up for weeks awaiting a coroner’s report, is now stuck pending a private contractor’s analysis of the Taser used to administer repeated jolts to Ms. McKenna.

Sheriff Stacey A. Kincaid, who waited more than two months to suspend the use of Tasers in the jail, has released virtually no information about the case or investigation. She has also declined to discipline or transfer the six guards who subdued Ms. McKenna to duties that don’t involve interacting with inmates, pending the results of the investigation.

Even as an accounting of Ms. McKenna’s death remains mired in inertia in Fairfax, what’s become clear is just how commonplace it is that mentally ill inmates like her are subjected to physical abuse and mistreatment, including the casual use of stun guns, in the nation’s prisons and local jails.

A new report by Human Rights Watch — “Callous and Cruel: Use of Force against Inmates with Mental Disabilities in U.S. Jails and Prisons” — documents the routine brutality exercised by guards who are untrained and ill-equipped to deal with mentally ill people, who make up enormous proportions of jail and prison populations.

Jail and prison staff use “force in the absence of any emergency, and without first making serious attempts to secure the inmate’s compliance through other means,” according to the report, which details cases similar to Ms. McKenna’s, which unfolded when she resisted the guards’ attempts to remove her from her cell.

The report goes on: “Force is also used when there is an immediate security need to control the inmate, but the amount of force used is excessive to the need, or continues after the inmate has been brought under control.”

In Ms. McKenna’s case, she had already been fully restrained — her hands and feet shackled — when a guard, frustrated that she would not bend her knees to be strapped into a chair, shot her repeatedly with his Taser.

Ms. McKenna was not physically imposing. At the time she was shocked, she posed no threat to the guards, nor was there any risk she could flee. Taser’s user manual warns several times that repeated use of the weapon against a subject “could increase the risk of death or serious injury.”

Despite that, she was shot three times in the weapon’s “drive-stun” mode, which the manual says is “for pain compliance only.” And she was shot once with the weapon’s electrical prongs, designed to incapacitate a subject.

Ms. McKenna was incapacitated — permanently. She never regained consciousness after the struggle in the jail on Feb. 3 and died five days later.