The Boston Globe is reporting that federal prosecutors are investigating the Massachusetts prison system over the treatment of elderly and severely ill prisoners. The news comes after WGBH News and our partner the New England Center for Investigative Reporting released a series of stories on the state's growing elderly inmate population last year. NECIR senior reporter Jenifer McKim discussed the investigation and her work on the prison system with WGBH All Things Considered host Barbara Howard. This transcript has been edited for clarity.

Barbara Howard: So tell us about this federal investigation that's being launched.

Jenifer McKim: So the Department of Correction has confirmed that they are being investigated by federal prosecutors. Attorneys close to the case say that the focus of the investigation is looking into issues related to solitary confinement and the treatment of ill and elderly inmates in the state prison system. I spoke with criminal appeals lawyer Ruth Greenberg about the investigation. "They require federal oversight," said Greenberg. "The state is not doing the oversight. The Department of Correction is very powerful. It's the fourth largest budget in the state, it has a lot of clout, and there's simply no incentive for the Department of Correction to correct itself."

Howard: Now this issue of elderly inmates who are vulnerable in the state prison system is something that you looked into extensively last year. Remind us about what you found.

McKim: Correct. So Massachusetts has one of the oldest inmate populations in the nation, and the numbers have been going up largely because the inmates are getting older and also because of strict sentencing laws passed in the 80s and 90s. The state also is one of the last in the country to pass a compassionate release law to let out the sickest and oldest inmates.

Howard: In the course of your investigation you visited a lot of prisons. What did you see?

McKim: So we toured several prisons and saw places where the oldest and sickest inmates stay, They were basically like nursing homes behind bars - men in wheelchairs, with dementia.

Howard: Clearly when you're older you get more vulnerable, and federal data shows that inmates over 55 are twice as likely to be killed in prison. You saw some of that yourself when you did this investigation. Tell me some of the things you saw.

McKim: We talked to inmates who told us that the older seniors feel afraid, stuck in their cells, really afraid of the community of younger, gang-related inmates who are there. We actually obtained a video of a 72 year old man walking with a cane who was killed in the Souza-Baranowski maximum security prison in Shirley, with inmates milling around and a guard at his post. So inmates have told us that older inmates are afraid of leaving because of what can happen out there.

Howard: How do they get adequate health care in the prison system?

McKim: We've heard from many prison advocates and inmates themselves about the difficulties of obtaining health care while in prison. So a guy who needs chemo needs to get shackled and sent by ambulance to the hospital, shackled in a bed there. It's not the best way to be treated. There are lots of stories of incontinent men who are left in diapers and not treated when they're sick. The only time they can ask for help is to actually put a note in a mailbox in the prison and wait for someone to come help them.

Howard: Some may believe that this is what the state wanted when these inmates were sent to prison. Why should people care?

McKim: So there are definitely people who say "I have no sympathy for these people. They committed crimes, they were supposed to be sentenced to life, and they should die in prison." But there are questions about us as a society. First of all, it's very expensive to care for elderly inmates. The statistics show that it costs two or three times the amount of money when you send an inmate to the hospital run by the prison system - it's something like nearly $300,000 a year to care for them. We found one inmate where the county sheriff's department spent about $2 million just to care for them as they awaited trial. So it's very expensive. Others argue that as a society, is this what we want to do?

Howard: Are these prisoners dangerous at this point?

McKim: The other question is, why do we have them in there and are they any risk to us at this point? A lot of these men that we met are in wheelchairs, and some of them can't even remember why they're there.

Howard: So they're not really a danger anymore.

McKim: That's the argument.

Howard: That's Jenifer McKim from our WGBH News partner the New England Center for Investigative Reporting, talking with us about her work looking at the way the elderly and the ill are treated in Massachusetts prisons. News out today is that federal prosecutors are now investigating the state's prison system. This is WGBH's All Things Considered.