GILMER – An Upshur County man will be serving a long prison sentence after being convicted of sexual assault of a child. Cory Martin Colvin, 34, of Naples, has been sentenced to 99 years in prison. He will not be eligible for parole for at least 30 years. According to KETK, testimony showed the former prison guard moved into a home with a co-worker outside of Gilmer in 2012. In 2013, he was said to have molested several girls under the age of 13.