When the U.S. started shutting down large institutional mental health hospitals in the 1960s — facilities that had become infamous for their poor conditions and subpar treatment — they didn't actually stop institutionalizing people with mental illness. They just started doing it in jails and prisons instead.

The big picture: Nearly half of the roughly 740,000 people being held in American jails have been diagnosed with a mental disorder and about a quarter are in "serious psychological distress," according to a new and impressive investigation by the Virginian-Pilot and Marquette University.

They’re trying to get a handle, despite subpar data, on mentally ill people who have died in jail. That doesn't include prison — only people who are waiting for a trial.

The investigation details several cases in which desperate families turned to the police for help, or a mentally ill person was arrested for a minor crime — driving on a suspended license, stealing from a 7-Eleven, marijuana use — only to end up dead months or even days later.

The warning signs were clear. Many of these patients had known mental health histories, often with their families pleading for help. Or the patients had outward signs like smearing feces on the walls.

Roughly 40% of the deaths the Pilot tracked happened during or after a stint in solitary confinement, which has been shown to aggravate mental illness.

The big picture: As the newspaper puts it: "A mental health crisis leads to an arrest, which leads to poor treatment of the illness, which leads to death."

Go deeper: The full piece is worthy of your time.