WALL, N.J. -- A New Jersey school district has suspended a teacher after yearbook photos of two high school students were altered to remove President Donald Trump's name on their clothing.

Wall Township School Superintendent Cheryl Dyer told News 12 New Jersey on Monday the yearbook's adviser was suspended while an investigation is underway. Further details about the suspension and the investigation were not disclosed, and Dyer did not immediately respond Monday to an email from The Associated Press seeking further comment.

However, it remains unclear who altered the yearbook photos or why. A spokesman for Jostens, the company that takes the photographs and prints the yearbooks for the district, did not respond to requests for comment on Monday.

One student wore a sweater vest with Trump's name on it. Another student wore a T-shirt emblazoned with the words "Trump Make America Great Again." But neither feature appeared in the photos published in the yearbook.

The only reason a student's image would be altered is if it was in violation of the district's dress code, such as clothing referencing drugs, alcohol or violence, Dyer has said.

The district also is probing why a Trump quote submitted by the freshman class president wasn't included under her photo, while a quote by President Franklin Delano Roosevelt appeared under the senior class president's photo.

Joseph Berardo Jr., the father of one of the students whose photo was altered, has called on the school district to republish the yearbooks at the district's expense with the unaltered photos. He said the problem would be "equally" as egregious if images of clothing supporting Democratic presidential candidate Hillary Clinton also had been altered.