On a quiet Sunday morning, March 5, 2023, a welfare check at a home on Brunswick Road in Fish Lake Township, Minnesota, led to a grim discovery. Kirk Patrick Mattson, a 47-year-old Caucasian male, was found deceased inside the residence, the victim of multiple gunshot wounds. He was not alone; his parents, 73-year-old Darrell James Mattson and 68-year-old Denise Lillian Mattson, were also found dead, having suffered the same fate. The tragic event unfolded after family members grew concerned when they were unable to reach Kirk or his parents.
The investigation into the triple homicide quickly focused on a person of interest. Authorities announced that a relative, 39-year-old Kenneth G. Koslowski of North Branch, was connected to the case. Koslowski had been found dead a day earlier, on March 4, in a rural area of Dakota County from what was determined to be a self-inflicted gunshot wound. The gun found with Koslowski was forensically linked to the evidence recovered at the Mattson family home, solidifying his connection to the killings.
Investigators believe the shootings were not a random act of violence and have assured the public that there is no ongoing threat to the community. While a clear motive has not been publicly released, the investigation by the Chisago County Sheriff's Office and the Minnesota Bureau of Criminal Apprehension has led them to suspect that Koslowski was responsible for the deaths of his three relatives before taking his own life. The case continues to be investigated to determine the full circumstances that led to the tragic loss of three members of the Mattson family.
