BELFAST, Maine — A former Searsport District High School softball coach was indicted last week by the Waldo County grand jury on a charge of sexual exploitation of a minor.

Matthew Cox, 35, of Stockton Springs was arrested in Winterport in December 2015 after a months-long investigation of claims there was an inappropriate relationship between the coach and a student athlete.

When Searsport police first learned about the allegation against Cox, the school removed the softball coach from his position. During the investigation, police received search warrants for the cellphones of both Cox and the alleged victim, a 16-year-old girl, after learning that incriminating photos and text messages might exist.

Cox was released after posting $10,000 cash bail.

If convicted of the Class B charge of sexual exploitation of a minor, Cox could be punished by up to 10 years in prison and a $20,000 fine.