A listener note, this episode contains descriptions of graphic material and references to suicide and may not be suitable for a younger audience. It's November 9th, 2017, in a ballroom on the campus of Boston University.

Dr. Anne McKee is standing off to the side of a stage, clutching her laptop,

as she watches a large crowd filter into the room.

McKia is a neuropathologist and researcher who studies the human brain.

She has blonde hair and is wearing a dark jacket and a pressed white button-up, a conservative outfit that's fitting for today's

event, an annual medical conference hosted by the university.

As part of the event, McKee has been scheduled to present her latest findings. But as she

looks out at the ballroom, McKee can see she's about to speak to a far

different crowd from the usual gathering of academics and medical scientists.

The ballroom is filling up with local and

national news reporters. They're carrying microphones and cameras and there's a

buzzing sense of anticipation as the crowd waits for McKee to address what's now becoming a national

news story.

McKee has spent years studying a degenerative brain disease called chronic traumatic encephalopathy

or CTE. The disease is associated with the kind of head trauma

experienced by soldiers in combat or victims of physical violence, but McKee, who runs a university center focusing on CTE, has cultivated a specialty

for analyzing the brains of deceased athletes, and recently she examined the brain of a man

who might be the most high-profile athlete yet.

Aaron Hernandez was once among the most promising young players in the NFL.

But after just three seasons with the New England Patriots, Hernandez was arrested and convicted of murder.

Then, earlier this year, at just 27 years old, Hernandez died in prison.

The following day, Hernandez's family donated his brain to McKee's lab for analysis, and it was

...