The risk of being killed during a police incident is 16 times greater for individuals with untreated mental illness than other civilians, according to a new report by the Treatment Advocacy Center (Tac). The report suggests that a variety of institutional and policy failures have often left law enforcement as the only available resource to deal with people in mental health crisis, sometimes with fatal results.

“If you have these situations in communities where, when someone is really sick, the only call the family can make is to law enforcement; of course you’re going to see these sort of tragedies happen,” said John Snook, executive director of the Virginia-based nonprofit, which works to eliminate barriers to the treatment of severe mental illness.

“People don’t stop getting sick just because you don’t have hospital beds for them, they have to go somewhere, so they go to the places that can’t say no,” Snook said. Often, those places turn out to be either emergency rooms or local jails. Twenty percent of America’s prison and jail beds are occupied by people with severe mental illness, the report said.

According to Tac, an estimated 7.9 million Americans live with a severe mental illness, and about half of this population does not receive the necessary care on any given day. It is this untreated population that is disproportionately likely to be harmed in an engagement with law enforcement.

Matthew Ajibade, who died after an altercation in a Georgia jail in January might be considered an example of this type of vulnerability. Ajibade, who had bipolar disorder, was arrested after a domestic disturbance involving his girlfriend, and was beaten and struck with a Taser several times at the facility. He died of blunt force trauma, and nine of the officers involved were eventually fired.

The study comes just as the FBI and Department of Justice have announced plans to expand and relaunch each of their individual efforts to collect data on fatal interactions between civilians and police. According to Tac, one of the primary roadblocks to addressing the issue is a lack of reliable government data.

“To some degree, the failure to track the role of mental illness in fatal police encounters is symptomatic of the failure to systematically track fatal police encounters, period,” the report reads.

The Guardian, the Washington Post and a former FBI investigator’s “True Crime” blog have all independently found that about 25% of fatal police incidents involve a mentally ill victim, the report notes. Currently there is no comprehensive government source for this information. The new DoJ program is expected to track mental health information. A spokesperson for the FBI did not immediately return requests for comment.

The startling statistic noting 16 times greater risk of a fatal encounter with law enforcement for people with mental illness was calculated using the 25% number reported by the Guardian and other publications, which Snook said made the estimate “very conservative”. The Guardian’s Counted investigation monitors whether mental health issues are identified by family members, friends or police.

The Tac report cites psychiatric deinstitutionalization, the process of emptying and closing psychiatric hospitals in favor of pharmaceutical and other less extreme treatment strategies, as a major driver of these disproportionate police contacts. From 1950 to date, the number of psychiatric beds plummeted by about 90% according to a Tac study. As this happened, according to the report, the community health centers meant to replace the institutions were neglected.

This process picked up speed roughly around the same time that the idea of “community policing” began to put more officers onto the streets and encouraged them to engage in more frequent contact with civilians. “In this environment, studies consistently find that 10-20% of law enforcement calls involve a mental health issue.”

The report recommends shifting the responsibility for dealing with mentally ill individuals to professionals in that field, and away from police, as well as an overhaul in the way the police killing data is collected, to ensure mental health issues are captured. It also suggests that lawmakers consider the “taxpayer savings that result from providing treatment that reduces criminal justice involvement”, along with treatment cost when making funding decisions.”