Imagine if you had been convicted of murder and spent the first decade of your prison sentence branded a cold-blooded killer and malingerer, all while enduring a relentless stream of beatings. Now imagine that on your 19th year of incarceration, the governor finally agrees to grant you clemency and move you into a hospital for treatment. But then you find out that there is a reason why you were sent to prison in the first place.

In 2009, Benjamin Gilmer, a newly minted M.D., took a job at a rural clinic in the mountains of North Carolina. It wasn't long before he learned that another doctor named Gilmer had worked there before him and had gone to prison after murdering his father.

At first, Gilmer thought his predecessor must have been a great doctor and a wonderful person. But as time went on, he became more and more convinced that his colleague was a man who had suffered from serious mental illness — including undiagnosed Huntington's disease, an inherited neurodegenerative disorder that slowly erodes brain cells and causes symptoms like twitching, paranoia, and irrational fear.

So he began to visit Vince in prison and, along with This American Life host Sarah Koenig, set out to try to understand what had happened to him. Their investigation turned into a book, The Other Dr. Gilmer, which delves into his research and comes to the conclusion that a judge should have sent Vince to a hospital instead of a maximum-security prison called Wallens Ridge in far western Virginia.