The acquaintance reported him to a citizen's group that helps track down people who violate the quarantine. The group then reported him to authorities.
Cooper, a teacher at Campbell High School, traveled to Florida because of an illness in his family, his attorney, Rustam Barbee said Wednesday.
After his arrest, he resumed his quarantine period, which ended Monday, Barbee said.
Cooper was arrested a week after teachers statewide returned to work. It's not clear if he had been on campus before his arrest.
“We can confirm that Mark Alan Cooper is a teacher at Campbell High School, and that this individual requested the appropriate leave for quarantine purposes,” State Department of Education spokesperson Drew Henmi said in an email.
The department declined to provide details about when he requested leave, citing a need to protect his privacy as an employee.
Student instruction begins Monday, with most schools starting the year online.
A news release from the Hawaii COVID-19 Joint Information Center announcing his arrest didn't mention he's a teacher.
“Mr. Cooper has never had COVID-19 and has never infected anyone,” Barbee said.
A court hearing is scheduled for Aug. 25.
According to court records he was cited in April for violating emergency orders by allegedly walking in a park that was closed because of the pandemic.