A former teacher at Mt. Ararat High School in Topsham has been indicted on a charge of possessing sexually explicit material of a minor under 12, court documents show.
According to court records and police reports, 32-year-old Nathan L. Valentine, of South Portland, is charged with knowingly possessing or accessing material that depicts a child under 12 “engaging in sexually explicit conduct.” The indictment says Valentine possessed the material in Portland in January 2025.
The Class C charge is a felony-level crime with a maximum sentence of five years in prison.
Valentine was the subject of a criminal investigation last year that Maine School Administrative District 75 officials acknowledged at the time, though they did not name him or specify the nature of the investigation.
In May, district Superintendent of Schools Heidi O’Leary held a press conference at Mt. Ararat High School in which she acknowledged a “deeply unsettling” situation involving someone she described as a former employee of the district.
Reporting by the Portland Press Herald first linked Valentine to the May announcement. A Harpswell Anchor review of past school board agendas confirmed that he had been an art teacher at the high school, and that his resignation was announced publicly in June 2025.
Valentine allegedly failed to appear for a scheduled arraignment hearing on Thursday, Feb. 19, and was arrested in South Portland the following day “without incident,” according to a Portland Police Department news release issued Tuesday, Feb. 24.
Court documents say Valentine’s bail was set at $5,000, and that he is barred from viewing or possessing sexually explicit material or devices capable of internet access. He is also barred from having any contact with minors under 17.
No other information was available regarding the details of the investigation or when Valentine will appear in court.
Valentine could not be reached for comment, and court documents do not list an attorney for him.
