This story explores suicide. If you are at risk, please stop here and contact the National Suicide Prevention Lifeline for support: 1-800-273-8255

Just days before Evan Hansen walked into the woods and died by suicide, he opened his laptop and searched CTE.

The 21-year-old senior football player at Wabash College in Crawfordsville, Indiana, also searched on his computer for Jason Hairston, a former college star who played in the NFL and had just died by suicide. Hairston was later found to have CTE.

Evan's parents, Chuck and Mary Hansen, knew their son had been struggling. They didn't know to what extent. They knew he had been getting help for depression. They didn't know how deep it had gotten.

When Boston University scientists asked the Hansens if they could study their son's brain after his death, their answer was yes. Evan's brain was tested for CTE or chronic traumatic encephalopathy, a neurodegenerative disease linked to repeated blows to the head.

A year later, Chuck and Mary got their answer.

Researchers told them the folds of Evan's brain and top of his spinal column were dotted with the plaque tau — abnormal accumulations of protein that collect inside neurons. He had developed CTE, an incurable disease.

Chuck Hansen believes his son diagnosed himself.

"I think Evan thought he had CTE or some type of injury from playing football," he said. "He was kind of determined to try to figure out a solution."

Evan had been proactive about getting help for his mental health issues and had been on a few medications. Hansen said those drugs "always made him worse." Less than a month before he died, Evan was put on a new antidepressant, his dad said.

"At times it seems like he was controlling it," Hansen said. "Then there were times it was much more difficult for him."

'He was able to hide everything'

The morning he died, Sept. 10, 2018, Evan made three phone calls to 911 but hung up each time.

"He never said a word on the calls," Chuck Hansen said. "We can only guess what he was thinking."

Hansen said he realized something was wrong when he looked at the navigation signal on Evan's phone. The locator had been in the same spot for quite some time. He followed the signal and found Evan's body in the woods.

Just two days before, after a 16-13 Wabash win, Evan had walked with his parents at halftime for senior day. The family celebrated with dinner at The Creekside Lodge in Crawfordsville.

Evan, a 6-foot-1, 200-pound linebacker and team captain, was the middle son of three boys — a gentle guy off the field but a tornado on it. Hansen remembered how Evan was flashing his goofy smile as they ate dinner. They said goodbye, just as they always did.

Evan went home to his Beta Theta Pi fraternity brothers that Saturday night. On Sunday, he showed up for a meeting with his football coaches.

“He didn’t let on to anyone. Nothing,” said Hansen. “He was able to hide everything from everybody. On the outside, he is still smiling and looking to the future.”

On the inside, the charade was over.

At the time of his death, Evan had been playing football for 14 years, since he was a rambunctious 7-year-old. He played varsity as a freshman at Guerin Catholic High School in Noblesville. On the field at Wabash, Evan was fearless and loved by his teammates. He liked to make up handshakes with other players and dance to celebrate on the sideline. He was a deep-thinking, kind soul, too. Evan was majoring in biology and Spanish with plans to become a nurse working in underprivileged countries.

The Hansens chose to go public with their son's story in an effort to help others, to bring awareness to the need for research on CTE.

"We are trying to shed light on a story that is kind of easy to sweep under the rug," Hansen said.

CTE can express itself in the form of memory loss, confusion, impaired judgment, impulse control problems, aggression, depression and anxiety, among other issues, said Thomas McAllister, a neuro-psych physician with Indiana University Health and an expert on CTE.

Research on how the disease affects the brain -- as well as how it affects those with CTE -- is an area that continues to be under rapid development, he said.

"At this point in time, the definitive diagnosis can still only be done after death," McAllister said. "What would be nice would be to develop some of these criteria in advance."

And McAllister cautions people not to self-diagnose CTE.

"The danger here is if people say, 'OK, I'm depressed and I'm a football player and therefore I have CTE,'" he said. "That is really not a logical inference."

Depression is treatable.

"At any age, whether you are worried about CTE or not, if you have depression, forget about the cause," he said. "It is something to get help for."

He was 'the rock of the world'

Many factors led to Evan's death, Chuck Hansen said.

"A combination of five or six things we think contributed to him dying," he said, "someone that seemed like the rock of the world."

There was the underlying CTE but also Evan's new medication. There was the stress of school and football, and Evan was extremely fatigued because he had been having trouble sleeping, his dad said. Then there was that CTE computer search that likely hit Evan hard, when he suspected he had the progressive disease.

"Someone called it a perfect storm or imperfect storm," Hansen said. "It's not one of those things alone that was enough. But all those things culminating at this one point."

Linking CTE alone to suicide isn't something scientists are ready to do, said McAllister, because such a selective group of people makes their brains available for autopsies after death.

"It's a very highly selective patient population," he said.

For the Hansens, donating Evan's brain was an effort to accomplish two goals: More CTE research and finding ways to make sports safer.

"We’re not telling people to never play football or never do any contact sports," Hansen said. "But how can it be safer and what is safe? What is safe enough?"

The Hansens said they don't blame football or Wabash in any way for their son's death.

"Our goal is not to make this a blame game," Hansen said. "It doesn’t matter. There is no money that can ever fix any of this for us."

Getting help

Crisis Text Line provides free, 24/7, confidential support via text message to people in crisis when they dial 741741.

When in doubt, reach out: National Suicide Hotline, 1-800-273-8255

For information and other resources: American Foundation for Suicide Prevention.

Follow IndyStar sports reporter Dana Benbow on Twitter: @DanaBenbow. Reach her via e-mail: dbenbow@indystar.com.