The mistrust between American law enforcement and its citizens likely hasn’t been higher since at least the tumultuous late-1960s, when the Civil Rights movement culminated with Chicago police brutalizing protesters at the 1968 Democratic National Convention.

Over the past few years, we’ve seen evidence of this unease and hostility from coast to coast, with numerous controversial deaths at the hands of law enforcement inspiring the #BlackLivesMatter movement and subsequent protests popping up around the country. The entire situation promises to be a prominent issue in the 2016 presidential race.

Now, it’s landed in Denver. On Thursday, Denver District Attorney Mitch Morrissey released a letter explaining his decision to not file criminal charges in the November 2015 death of inmate Michael Marshall, despite the fact that the city’s medical examiner ruled his death a homicide.

Marshall was being restrained by Denver Sheriff deputies this past November at the Downtown Detention Center when he vomited; the medical examiner notes that “[c]opious emesis [vomit] was noted in the airway requiring suction. He was transported by ambulance to a nearby medical center where he was diagnosed with diffuse anoxic brain injury, respiratory failure, acidosis, mild rhabdomyolysis, hypertension, and pneumonia. Blood and respiratory cultures were positive, consistent with aspiration.” After losing consciousness during the incident, Marshall never awakened. His family took him off life support nine days later. Multiple cameras inside the jail recorded the incident, and officials released them to Marshall’s family and the media by Friday morning.

Despite the presence of those cameras (but no audio) and nearly an hour of video footage that shows the incident unfolding, it’s still not entirely clear what happened. The officers watching Marshall at first aren’t acting aggressively toward him, other than ordering him to sit on a bench. (Given that Marshall was a schizophrenic who had refused his medicine for the previous few days and is visibly agitated in the video, this was the appropriate tack.) When Marshall rises and moves toward the wall where one officer is standing, it’s not clear whether Marshall was beginning to faint, or if he was trying to move past the officer before that officer and several colleagues swung Marshall back toward the bench, down to the floor, and began restraining him.

It wasn’t much of a struggle. Marshall’s body, now mostly out of frame, appears to go limp fairly quickly, and within minutes the deputies have summoned medical personnel. The most damning part of the videos shows a semi- or unconscious Marshall being strapped into a chair as at least a half-dozen officers and medical personnel hover around him for several minutes. One officer lightly thumps Marshall’s chest and takes his pulse, then suddenly he and several others descend on the chair’s restraints, feverishly undoing them so they can move Marshall to the floor and begin administering CPR. The last 14 minutes of one of the videos shows the officer futilely performing CPR while his colleagues look on or assist.

The biggest legal question the videos raise is why the deputies didn’t get the obviously incapacitated Marshall emergency medical assistance more quickly. But because prosecutors tend to pursue only the cases they think they can win, these videos are inconclusive at best about whether the officers acted within the rules. So from Morrissey’s persective, their actions weren’t egregious enough to convince a jury that anyone committed a homicide. Although they do suggest a certain level of negligence about Marshall’s dire condition, there’s nothing in them (that we can see) that shows any officers acting violently.

The other thing prosecutors tend to do is protect their own. Admitting mistakes, especially ones involving negligence or violence resulting in death, has never been one of law enforcement’s strong suits in Denver or anywhere else. Unless there’s other evidence of police misconduct during this incident—the lack of audio means we have no idea what was being said—any criminal case Morrissey might bring based primarily on the video footage wouldn’t be very strong.

That doesn’t make Marshall’s death any less concerning. After all, this is the second time someone has died at the hands of law enforcement inside the Detention Center since 2010. That episode was part of a series of troubling incidents that led to the hiring of a new sheriff this past October, the most recent development in Mayor Michael Hancock’s attempts to make law enforcement reform a centerpiece of his administration. He previously hired an outsider, Chief Robert White, to oversee the reform efforts in the police department, even though the Denver police union has openly and actively resisted many of these proposals.

Moreover, Morrissey’s track record of holding law enforcement accountable for violations of any kind is virtually nonexistent. It’s logical to question his judgment about Marshall’s case and about the many other excessive force allegations against that department that he’s also declined to prosecute.

We hear a lot of lip service from City Hall about supposedly sincere desires to reform an institution whose history, both recent and long ago, is stained with isolated incidents and systematic examples of unethical, violent, and sometimes deadly misconduct by those whose primary duty is to serve and protect. Until someone truly has to answer to such charges, that rampant mistrust between citizens and law enforcement will only increase.

Editor’s note, 1/23/16: A previous version of this story incorrectly stated that Denver District Attorney Mitch Morrissey would not file criminal charges against any police officers; it was in fact deputies employed by the Denver Sheriff Department that are pictured in the video and involved in this case. The article has been updated to reflect this. We regret the error. Additionally, the article was updated to include more details regarding the autopsy report’s findings.