A suburban Chicago man has been sentenced to 12 consecutive terms of life in prison for sexually abusing children over 10 years.

David B. Libby of Plainfield was sentenced Tuesday after being found guilty in March of predatory criminal sexual assault of a child.

Will County prosecutors say the 52-year-old began sexually assaulting the children in 2004 and continued through 2014. The abuse came to light when a teacher contacted a school social worker after one of the children made a troubling comment on a written test.

The student eventually reported the abuse to the social worker, who contacted police. Libby admitted to sexually assaulting the children when interviewed by police.

Will County State’s Attorney James Glasgow said it took “tremendous courage” for the victims to come forward and testify.