A Knoxville man who was found responsible for his mother’s death at a civil trial but acquitted at a murder trial is now suing criminal investigators and his father. Forty-seven-year-old Jason Carter filed a federal lawsuit Thursday (12/12) accusing investigators of conducting a biased and incomplete investigation into his mother’s death. Carter’s father, Bill Carter, won a wrongful-death lawsuit against his son in 2017. The suit alleged that Jason fatally shot 68-year-old Shirley Carter in June 2015 to gain access to his parents’ assets. Jason Carter was ordered to pay $10 million to his mother’s estate. This past March, a jury acquitted him of murder.