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A Michigan police officer has been placed on administrative leave after potential home buyers said they discovered Confederate flags and Ku Klux Klan paraphernalia while touring his home.

Robert and Reyna Mathis were with their real estate agent on Wednesday when they went to see the five-bedroom house that belongs to Muskegon Officer Charles Anderson. Upon entrance to the home, the couple saw the flags on the walls, in the dining room and in the garage.

But what the Mathises discovered in one of the bedrooms was even more shocking, they said.

“There’s a plaque on the wall. So, I walk over to the wall and I read the plaque and it said ‘KKK application.’ So, I was like, ‘I’m done,'” Robert Mathis told CNN affiliate WOOD.

The couple alerted their agent and ended the walk-through after seeing the application, which was in a wooden frame and did not appear to be filled out. Robert Mathis then took to Facebook to detail the experience he had with his wife.

“I feel sick to my stomach knowing that I walk to the home of one of the most racist people in Muskegon hiding behind his uniform and possibly harassing people of color and different nationalities,” wrote Mathis on Facebook.

Anderson wasn’t home when CNN reached out and his wife, Racheal, refused to comment, saying it was because the situation is currently under investigation. City officials on Thursday confirmed the investigation.

Racheal Anderson was asked by WOOD whether her husband was a member of the KKK.

“No, he’s not, no, no,” she said, chuckling. She added: “He can’t say anything right now, I wish we could because it would probably set a lot of things straight.”

CNN was unable to reach the Mathises on Friday.

Following an outpouring of support on Mr. Mathis’ post, the city of Muskegon responded with a Facebook post reassuring residents that “The officer was immediately placed on administrative leave, pending a thorough investigation.”

“The issue was only brought to our attention yesterday morning,” City Manager Frank Peterson told CNN. “Unfortunately, we have limited information at this time, so will be avoiding further comments until our investigation is complete.”

The Muskegon Police Officer’s Labor Council told CNN that the group does not comment on ongoing investigations as per their policy.