Inside Cook County Jail, about 30 inmates gathered in a windowless room to talk about what they would do if they found out their child was being bullied at school.

The young men first joked that they’d teach their sons to beat up the bully — or maybe go to the school and intimidate the tormentor themselves. But later they got serious, and contemplated whether there was a nonviolent way to deal with the situation.

“You want us to lead by example,” said one young man.

The men in this room, between 18 and 24 years old, are at the epicenter of Chicago’s violence. They’re what experts call “disconnected,” not working and not in school.

More men in their late teens and early 20s were killed or arrested for homicide than any other group in Chicago last year, according to the University of Chicago Crime Lab, which did a comprehensive study of violence in the city last year.

And almost all of those killed or arrested for murder had previously spent time in Cook County Jail, according to the study.

Last year, Cook County Sheriff Tom Dart started a program called SAVE, which brings in social workers and therapists to help these young inmates change their trajectory. But Dart found few organizations that would agree to work with him. The sheriff and other experts said a lack of funding and a high risk of young inmates returning to criminal behavior have kept potential organizations and employers from making a commitment to this age group.

Not helping these young men is a mistake, said Roseanna Ander, executive director of the Crime Lab.

“If we don’t do anything with that population, if we are not thinking about how to reach that population right now, we are going to continue to have high rates of violence,” she said.