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A seemingly innocent meeting between a South Dakota man and his local police chief to exchange a Christmas card devolved into a conversation with an accused murderer when the man allegedly admitted to the top cop: "I snapped," recent court papers show. 

Milbank resident Brent Hanson was charged Dec. 15 with the murders of his brother, Clyde Hanson; his sister-in-law, Jessica; and her unborn child, according to local KELO-TV and a probable cause statement obtained by the outlet. He allegedly attacked his brother with a baseball bat and Jessica with a machete. 

Details in the document describe the ominous statements and behavior exhibited by Brent Hanson, 57, shortly after the slayings. 

Hanson met with Milbank police Chief Boyd VanVooren around 9:10 a.m. Dec. 15 at the department offices, after the chief had arranged the meeting on Facebook the day prior, the document states. The purpose of the meeting was for the men to exchange "a Christmas card from a church."

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During the meeting, VanVooren asked Hanson about "any further issues" with two people who are identified in the document as "victim #1" and "victim #2," but who are identified by KELO-TV as Clyde and Jessica. 

Hanson told the chief: "they no longer live here," papers state.

Only minutes later at 9:45 a.m. local time, VanVooren heard a police radio call for a welfare check at the victims’ address, where a food delivery worker reported seeing what she thought was blood on the door.

VanVooren then asked Hanson where his brother had moved "and if there was blood on his door." 

"I snapped," Hanson allegedly replied, as he "made a motion with his thumb across his neck indicating a ‘slashing motion.’"

When the police chief asked again, Hanson allegedly repeated: "I snapped."

"I killed them on Sunday," he said, according to the document.

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According to the police report, Hanson and his brother were home alone when "he went up there with a baseball bat and wacked [his brother] in the head enough times so [he] was gone."

Jessica Hanson, who was nine months pregnant, was not home at the time. When she returned Monday morning, Hanson said, he "wacked [her] in the head with a machete, and that was the end" of her," the document states. 

"Brent said he totally flipped," the document further alleges. 

The Hanson brothers have joint ownership of the residential property where they both live in separate spaces, the Aberdeen American News reported.

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Brent Hanson had a previous scuffle with the couple in July, when he was arrested and charged with misdemeanor assault and domestic violence. Brent Hanson allegedly pushed around the couple after an argument over the care of Jessica Hanson’s dog.

After allegedly murdering his brother and sister-in-law on Dec. 12 and 13, Hanson took the couple’s 3-year-old child, and told the police chief, "the child was safe and that he fed the child," according to the papers.

Police searched the home just after 10:05 a.m. and found Jessica’s body under a blue tarp and Clyde’s behind sheetrock, both in a portion of the home that was "undone." The 3-year-old was discovered in the apartment within the home, sleeping, records show.

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Hanson has been charged with three counts each of first- and second-degree murder. Hanson is jailed on a $5 million cash bond. It was not clear if he had an attorney.

The Associated Press contributed to this report.