On a quiet Sunday, March 5, 2023, the peaceful lives of a Harris, Minnesota family were tragically cut short. Darrell James Mattson, a 73-year-old White/Caucasian male, was discovered deceased in his home alongside his wife, Denise Lillian Mattson, 68, and their son, Kirk Patrick Mattson, 47. Their deaths were the result of a shocking act of violence, with the Midwest Medical Examiner's Office later confirming that all three family members had died from multiple gunshot wounds.
The grim discovery was made after a concerned family member, unable to get in touch with them, requested that authorities perform a welfare check at their residence in Fish Lake Township. Deputies from the Chisago County Sheriff's Office arrived at the home to find a scene that would initiate a widespread investigation, shaking the small community to its core. Investigators from the sheriff's office and the Minnesota Bureau of Criminal Apprehension began to piece together the events that led to the triple homicide.
As the investigation unfolded, authorities announced they had identified a person of interest. This individual, however, was also found deceased at a separate location the day before the Mattson family was discovered. The person of interest was identified as Kenneth George Koslowski, a 39-year-old relative of the victims from North Branch. He was found in a rural area of Dakota County, having died from what appeared to be a self-inflicted gunshot wound.
Forensic evidence became the crucial link in the case. The gun that Koslowski used in his suicide was forensically matched to the evidence recovered from the homicide scene at the Mattson residence. Furthermore, investigators were able to determine that Koslowski had been in the vicinity of the family's home around the time the killings were believed to have occurred. While authorities have not publicly commented on a possible motive for the killings, they have stated that they do not believe the incident was a random act of violence and that there was no ongoing threat to the public. The investigation remains ongoing as authorities continue to seek answers in the tragic deaths of the Mattson family.
