A woman has been sentenced to 20 years in prison for keeping her three adopted children in cage-like structures. Brenda Sullivan, 51, kept her 17-year-old mentally disabled son in a wood cage as well as her two 13-year-old sons.

Sullivan claimed that a doctor prescribed the contraption to the mentally disabled teen. The doctor later testified that the crib was prescribed when the boy was 7-years-old and it didn’t have a wood covering. The two other teens also testified that they were kept in cage-like structures.

In January, Sullivan pleaded guilty to three counts of aggravated child abuse. Her husband, Wilson Sullivan, was charged with similar counts but died before the hearing.