The Texas attorney general's office says a 57-year-old member of a polygamist group has been sentenced to 33 years in prison for the sexual assault of a child.

The office says in a statement that a jury decided Thursday on the punishment for Allan Eugene Keate, the second member of the Fundamentalist Church of Jesus Christ of Latter Day Saints to be convicted on that charge.

The jury at a court in Eldorado, West Texas, deliberated for under two hours Tuesday before convicting Keate for his "spiritual marriage" to a 15-year-old girl who gave birth at age 16.

The prosecution's case largely relied on records seized from the polygamists' Yearning For Zion Ranch in April 2008, including some that indicated Keate had six wives aged 17 to 49 in 2007.