The lawsuit, filed in Jackson County, Mo., alleges that Belcher was subjected to "repetitive head trauma" during his four seasons with the Chiefs.
The lawsuit also alleges that Belcher "suffered multiple concussive and subconcussive blows to the head which caused or contributed to cause a a constellation of neurologic/brain harms, including post concussion syndrome... and traumatic brain injuries, such as Chronic Traumatic Encephalopathy (CTE)." Shepherd is seeking damages in excess of $15,000 in the suit.
Shepherd was in her son's home on Dec. 1, 2012 when he shot and killed his girlfriend before taking his own life a short time later in the parking lot of the Chiefs' team facilities.
At the request of his family, Belcher's body was exhumed earlier this month to look for possible evidence of CTE.
"If his brain had been examined (when he died), we'd have a better understanding of why he did what he did,” Dr. Bennet Omalu, the man credited with discovering the brain disease chronic traumatic encephalopathy (CTE), said earlier this month. "We would have a better understanding about concussions and playing football, and we would advance the understanding of the science of all of this."
Belcher's mother is suing the Chiefs on a total of four counts that include: the team was negligent in maintaining a safe working environment; they told Belcher his mental-health issues weren't related to any head trauma he suffered playing football; the Chiefs knew that CTE was a risk, but they concealed that information from Belcher and the team wrongfully contributed to his death.