A school superintendent and high school principal has been charged with three felony accounts for his alleged sexual relationship with a 15-year-old boy.

Charles Soper, 50, has been charged with luring a minor by computer, solicitation of a minor and human trafficking, according to The Bismarck Tribune.

Authorities believe Soper met the teenager on Grindr, a dating app for gay men. The relationship began last fall and continued through this spring.

The boy kept a calendar in which he claims he met Soper for sex 15 times.

According to the boy, a third party was usually involved in the sexual encounters, and Soper told the boy to not reveal his true age to the other people involved.

The boy claims he tried to end the relationship this spring, but Soper continued to harass him.

The boy’s parents contacted police, and Soper was arrested at school a few days later.

Computers and other evidence was removed from Soper’s home.

Soper has been placed on administrative leave by the Sawyer Public School System.

According to the Associated Press, Soper denies any wrongdoing.

Soper's bail has been set at $250,000, cash only. Soper complained in a court appearance that the bail was too high. The prosecutor said the amount was consistent with other human trafficking cases.

Soper’s next scheduled court appearance is June 11.