A new report from the Associated Press has found disturbing information about the death of former college football player Michael Keck.

Keck, a former player at the University of Missouri and Missouri State, died last year. Doctors say he died of a heart condition. However, new research shows he was also suffering from a severe case of chronic traumatic encephalopathy, or CTE, the disease widely known for being at the center of the NFL's player safety crisis.

A standout high school football player from Harrisonville, Mo., Keck was deemed a four-star recruit and signed to play with the Missouri Tigers. After two seasons at Missouri, Keck transferred to Missouri State. That's when things went downhill for him and his health.

The linebacker was knocked unconscious in 2009 during his first fall camp with the Bears. He eventually returned to the field but wasn't the same. He had memory and vision problems. He couldn't sleep.

According to the Associated Press story, Keck "turned combative — punching holes in the wall. He began to struggle in school. Soon he was spending most of his time indoors, with blankets covering the windows to darken the room."

Keck left the Missouri State football team in 2011.

"I think, if he had it his way, he'd still be playing," associate head coach D.J. Vokolek told the student newspaper, The Standard, at the time. "But it had gotten to the point that he was having so many concussions that it could affect him the rest of his life. After consulting with the doctors, we came to the conclusion that it was time for him to call it quits."

Keck died last year at the age of 25.

Doctors believe his cause of death was an unrelated heart condition. However, his brain, at his request, was donated to the Boston University lab that has been researching the degenerative brain condition CTE, which has been found in many contact-sport athletes.

The doctors who examined Keck's brain now say he had an advanced case of CTE rarely seen in someone so young.

"When you talk in terms of his age, being young, and you talk about his limited years of playing, it is one of the more severe cases,"  Dr. Robert Cantu, a co-founder of the CTE Center at BU told the AP. "Had he lived to 70 or 80, we would have expected this to be a Grade 4 (the most severe form) case."

Keck is survived by his wife Cassandra and their young son Justin, who is now three-years-old.

“It makes me happy for him because it’s what he wanted to prove to everybody,” Cassandra said. “He was really suffering, and nobody believed him.”

Missouri State spokesman Rick Kindhart says the school treats all of its student-athletes consistently and "with the current national standards of care."

“No student-athlete is ever cleared to return to practice or competition without first being free of concussion symptoms and then going through the appropriate return-to-activity progression process," Kindhart says.

For the full story, including more quotes from Cassandra Keck, read the AP's entire story.

RELATED: Contact Sports Don't Cause CTE, Study Says

Michael Gaio is eMedia Editor of Athletic Business.