A Utah woman whose 4-year-old son was malnourished, beaten and then killed has been sentenced to at least 20 years in prison for her role in the boy's death.

A judge on Monday sentenced 31-year-old Stephanie Sloop to 20 years to life behind bars for Ethan Stacy's 2010 death.

The Standard-Examiner reports (http://bit.ly/11dMttm ) that Sloop pleaded guilty to aggravated murder and obstructing justice under a deal with prosecutors.

Prosecutors say Sloop failed to stop her husband and Ethan's stepfather, Nathanael, from abusing her son and didn't call for help.

A medical examiner testified last year that the boy died of too many over-the-counter medications, severe burns and pneumonia.

Authorities say Nathanael Sloop then used a hammer to disfigure Ethan's face before burying his body. The stepfather is serving 25 years to life in prison.