Why would central booking turn the suspects away? Booking takes four to five hours in normal circumstances, so corrections officers want to make sure people are up to the ordeal, a spokesman told the Sun. It’s also a matter of cost: Once a prisoner is taken in, the detention center is responsible for providing medical care to them and shouldering the cost, since prisoners are constitutionally entitled to health care.

No one seems to doubt that prisoners do sometimes fake injuries; it’s conventional wisdom among police going back to before Gray’s death, as the ready slang term “jailitis” demonstrates. The question is how frequently it really happens, and how effectively police are able to tell the difference. In Baltimore, the answer appears to be that they’re especially bad at it.

One problem is that while police are trained first responders, they are not medical personnel, and they are ill-prepared to treat suspects. But the adversarial relationship of mutual distrust between police and suspects has to play a role in explaining the problem, too. When officers make arrests, they assume the detainees have committed crimes, and are likely to suspect that pleas for medical attention are mostly lodged to avoid jail.

In Baltimore, where there is serious and longstanding tension between the black community and the police department, there appears to be an elevated risk of improper arrests—for example, Mosby said Gray committed no crime, and she has charged officers with false imprisonment for arresting him. And in Baltimore there is also a long and ignominious history of police brutality. Those currents meet in the case of refusing medical attention to detainees:

The Sun's examination of more than 100 lawsuits against officers— in which the city paid more than $6 million in court judgments and settlements—found that dozens of residents accused police of inflicting severe injuries during questionable arrests and disregarding appeals for medical attention.

The newspaper also found that in other localities—including New York and Cleveland, both of which have also seen accusations of excessive use of force and other civil-rights abuses by police—there’s no comparable problem, and police are faster to seek medical care.

The swift and aggressive decision to charge the officers in the Gray case may make police faster to seek medical attention for detainees. Mosby charged officers with crimes including second-degree depraved heart murder, manslaughter, and assault, as well as misconduct and false imprisonment. While experts think Mosby may have overcharged the suspects, the possibility of quick prosecution will likely make officers err on the side of caution in the future. (Also over the weekend, attorneys for the charged officers called for Mosby to leave the case, citing what they called conflicts of interest.)