Jurors on Tuesday convicted the Fundamentalist Church of Jesus Christ of Latter Day Saints member over allegations from 2006.
The FLDS sanctions polygamous unions, which are not official civil marriages. The San Angelo Standard-Times reports Dutson would have been 20 at the time of the October 2005 ceremony. The girl would have been 15.
Defense attorney Brandon Hudson told jurors that the parents gave their consent and a ceremony was held.
Prosecutor Eric Nichols says the case was about sexual assault, not validity of search warrants used during a 2008 raid on the Yearning for Zion Ranch.