25-year-old Jovan Belcher, 25, shot and killed his 22-year old girlfriend, and them himself on December 1st 2012.
Belcher's mother, Cheryl Shepherd, claims in her wrongful death suit that the Chiefs knew her son had suffered complications relating to concussions, but that the team forced him to play through his injuries.
The suit says Belcher experienced memory loss, confusion, depression and explosive mood swings.
Belcher's mother is seeking at least 15-thousand dollars for four counts.
She is requesting a jury trial.
Shepherd filed the suit Friday in Jackson County Circuit Court. CBS affiliate KCTV says hers is the second concussion-related lawsuit filed on the last day of the year against the Chiefs.
KCTV reports: Former players Joe Horn and Tamarick Vanover, also sued on Friday, saying injuries suffered while playing for the Chiefs led to brain trauma, including Chronic Traumatic Encephalopathy. They are among the more high-profile players to file a lawsuit against the Chiefs over head injuries.
Belcher's mother recently had his body exhumed in order to examine his brain. The lawsuit does not reveal those results, but says Belcher suffered multiple concussions and blows to the head during his playing days.
Belcher was the middle linebacker for the Chiefs from March 2009 through Dec. 1, 2012. He was drunk when he fired nine shots into Kasandra Perkins' body inside their residence before driving to the practice facility, where he shot himself in the head in front of then-coach Romeo Crennel, a second coach and then-general manager Scott Pioli.
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