The man authorities say notified them he had killed his wife last Friday night in Blaine was charged with second-degree murder.
The criminal complaint alleges an impending divorce may have been the motive behind the fatal shooting.
According to the criminal complaint, Blaine police were dispatched to a residence following a 911 call from a male who stated he had used a gun to kill his wife. The man allegedly said the gun was unloaded and in the foyer of the home.
After arriving at the home, officers communicated with the man - identified as the 46-year-old Jansen - and directed him to exit the house without the gun. He then complied without incident, the complaint states.
Police then entered the home and found the body of a female lying on the floor of an upstairs bedroom. The woman - identified as 46-year-old Mary Jo Jansen - was determined to be deceased. Police also located an unloaded Smith and Wesson .44 handgun on the steps of the home and found two spent .44 cartridges in the bedroom where Mary Jo was discovered, the complaint said.
Matthew Jansen allegedly told officers "I can't believe I did it," and "I guess I don't have to worry about a divorce now." The complaint alleges detectives learned from family members that Mary Jo had served Matthew divorce paperwork around Thanksgiving.
The complaint states the two had remained in the home while the divorce was pending, but that Mary Jo had been planning to move out permanently on Saturday.
And the criminal complaint alleges an impending divorce may have been the motive behind the fatal shooting ...