The hearing is finally scheduled to end Friday, and a verdict on Mr. Freshwater’s fate is expected some months later. But the town  home to about 15,000 people, more than 30 churches and an evangelical university  remains split.

Image John Freshwater, center, in Mount Vernon, Ohio, in April 2008. Credit... Pam Schehl/Mount Vernon News, via Associated Press

To some, Mr. Freshwater is a hero unfairly punished for standing up for his Christian beliefs. To others, he is a zealot who pushed those beliefs onto students.

“Freshwater’s supporters want to make this into a new and reverse version of the Scopes trial,” said David Millstone, the lawyer for the Mount Vernon Board of Education, referring to the Tennessee teacher tried in 1925 for teaching evolution. “We see this as a basic issue about students having a constitutional right to be free from religious indoctrination in the public schools.”

Mr. Freshwater, who declined to be interviewed, has said he did not mean to burn a cross on any student’s arm. Instead, he said he intended to leave a temporary X on the skin using a device called a Tesla coil during a science demonstration. He says he had done that, with no complaints, hundreds of times in his 21 years as a teacher at Mount Vernon Middle School.

In a radio interview in 2008, he said he had been a target for removal since 2003, when he proposed that the school board adopt a policy to teach evolution as theory, not proven scientific fact. “I ruffled some feathers,” he said.