Between the lines: Barr did not elaborate about the specific irregularities, but union officials have long been warning about a "severe staffing shortage at the facility in the wake of a federal hiring freeze," per the New York Times.

• The American Federation of Government Employees, which represents 700,000 workers, wrote on Twitter Monday: "For years, our union has been sounding the alarm about the hiring freeze instituted by President Trump in the Bureau of Prisons, the thousands of staff vacancies that have resulted & the dangerous conditions these staff shortages have created for workers and inmates."

Barr's full statement:

This case was very important to the Department. It was important to the dedicated prosecutors and agents who investigated the case and were preparing it for trial. Most importantly, this case was important to the victims who had the courage to come forward and deserved the opportunity to confront the accused in court.

I was appalled — indeed, the entire Department was — and frankly angry, to learn of the MCC’s failure to adequately secure this prisoner. We are now learning of serious irregularities at this facility that are deeply concerning and that demand a thorough investigation. The FBI and the Office of Inspector General are already doing just that. We will get to the bottom of what happened at the MCC and we will hold people accountable for this failure.

Let me assure you that this case will continue on against anyone who was complicit with Epstein. Any co-conspirators should not rest easy. The victims deserve justice, and we will ensure they get it.

Go deeper: What we know: The life and death of Jeffrey Epstein

The big picture: Political and economic power is shifting to the cities, and 20% of the population — 46 million people — is being left behind in the middle of America. These communities face increasingly difficult barriers to education, wealth and health.

• And if you're African American or Hispanic, your chances of success and survival at every turn are even worse.

Let’s say you were born, grew up and now reside in rural America. Throughout your life, you have been more susceptible to poverty, lower education, illness and even death than your urban counterparts.

• As a kid, chances are, you lived farther away from a doctor or hospital and got less exercise.
• You were more likely to live in a school desert — having to travel long distances to make it to school, if you were able to attend at all. Your school might have shuttered, as school consolidation has become more common in many rural areas, per the New York Times.
• You had a greater likelihood of getting your high school diploma than the national average, but were far less likely to go straight to college than your urban and suburban counterparts, as The Atlantic reported.
• If you did graduate with a college degree, you'd likely end up so saddled with student debt that returning to your rural hometown wouldn't be an option if you hoped to get a job that would enable you to pay it off, according to research by the Federal Reserve.
• Even if you stay, some of the brightest people you grew up with would leave, contributing to the rural "brain drain."
• As an adult, you’re more likely suffer from obesity, mental health issues, diabetes, cancer and opioid addiction. You are more likely to know people who took their own lives.
• If you keep working in your hometown, your job is more likely to be taken over by AI, according to a study by the Brookings Institution — especially if you live in Indiana, Kentucky, South Dakota, Arkansas or Iowa.
• Your community's economy still hasn't fully recovered from the 2008 recession, according to Fed data.
• As you get older, you are more likely to die from a preventable death, according to the Centers for Disease Control and Prevention.
• If you do make it into old age, you may not have a place to grow old near your friends, family and the place you called home your whole life.

What's next: Technological advancements such as 5G and automated vehicles won't directly make life harder for rural America, but instead will fuel inequality by making life that much easier for urban America.

• The rural-urban divide will continue to play a central role in politics and elections for the next several years — unless and until rural America's population declines enough that its political power dwindles.

The bottom line: States, municipalities and the federal government have spent billions to draw jobs and prosperity to stagnant rural areas. But not much has changed.

Go deeper:

• Why rural counties are dying in America
• How 5G may widen the rural-urban digital divide
• Tough times in farm country
• Where automation will wipe out the most jobs in the U.S.