Slain MI Wife Accused Killer Husband Of Cheating With Younger Intern: Report

GRAND HAVEN TOWNSHIP, MI — A Michigan woman who was killed alongside her six kids by her husband last week once accused him of cheating on her with a younger intern, according to a report.

Kristopher Karolkiewicz, 47, fatally shot his wife, 39-year-old Amanda "Mandy" Karolkiewicz and their kids—ages 5 to 15—Friday inside their Grand Haven Township home before starting a fire and shooting himself, according to police.

Roughly two years ago, Amanda Karolkiewicz wrote dozens of posts across a Reddit account with the username "MandyK1179," according to a Holland Sentinel report, which said the outlet "confirmed the authenticity of the account."

Amanda first described how she first met her older husband while she was working as an intern and that she was "living in a Hallmark Movie," according to the report.

Further posts, however, showed a darker marriage, including a post in which she accused her husband of cheating on her with a younger intern.

The outlet reported that Amanda frequently posted in the subreddit "As One After Infidelity," which is a peer support group for reconciliation after cheating, where she said she wouldn't have tried reconciliation if it weren't for their kids, writing, "I love my kids more than I hate my husband right now."

In a 2024 post, she described the prospect of leaving with six kids as "insanely terrifying," adding that her husband "had major red flags that I ignored due to my own trauma and anxious attachment."

Amanda said in the lengthy Reddit post that her husband was raised in a toxic family dynamic that "encouraged lying about everything." She said she had caught him in the "dumbest lies," but usually dismissed them as "stupid, minor, and not worth it."

The post, which says Kristopher was "super angry" after marriage counseling, outlines how Amanda caught her husband being "sneaky" and suggested the two go to marriage counseling after she caught him being "sneaky." She also talked about how she noticed later that night her husband couldn't sleep and that he was angry and mad at himself because the counselor asked him if he heard Amanda.

"It seems like SUCH a big reaction to that pretty normal question from a marriage counselor," she wrote in the post. "He is SO sensitive to correction that I’m feeling so discouraged that we’ll ever be able to make progress."

A separate post roughly three years ago in the life insurance subreddit shows Amanda was searching for insurance for her husband, who was born with two heart defects. She said they had experienced a layoff a year earlier, saying, "Itfrightening to be without life insurance during that time (we have six kids)."

The murder-suicide also came just weeks after Kristopher Karolkiewicz's employment at the American Heart Association ended, a family friend told 13 ON YOUR SIDE.

The organization told the news station that Kristopher served as the national vice president of sales and marketing and worked from home.

Amanda Karolkiewicz was a beloved substitute teacher at Grand Haven Area Schools.

"Mandy goes above and beyond for students, especially when they’re having a hard day, responding with empathy, patience, and care. She pours her heart into her work, is always willing to help wherever needed, and helps make Peach Plains a better place to learn and work," a Facebook post highlighting her work earlier this year.

The couple was together for 17 years before they and their children were found dead inside a burning home last Friday, according to officials.

Officials did not identify the children but said the couple had four boys, ages 15, 12, 11, and 5, and two girls who were both 11 years old. Two of the children were adopted, officials added.

Officials were still investigating the cause of the fire, but said they believe the fires were intentionally set in multiple areas of the home.

Officials do not believe there are any other suspects involved in the incident.

They ask anyone with information about the shootings to call the Ottawa County Sheriff's Office at (616) 738-4000. Tips can also be submitted anonymously through Silent Observer at (877) 88-SILENT.