Published: Dec 21, 2012 11:03 AM EST

SARASOTA, Fla.- The Sarasota County Sheriff’s Office has arrested 35-year-old Misty Stoddard, of 9021 Delft Road, for abusing her 11-year-old step-daughter who died on Monday.

The medical examiner determined Melissa Stoddard died from hypoxia, which is caused by oxygen deprivation. Doctors who tried to treat her when she was hospitalized December 12th found she had severe brain damage, ligature marks and lacerations on several parts of her body.

The victim’s father, Ken Stoddard, was arrested Wednesday. Ken described how he and Misty “restrained” Melissa, who has autism, and claimed it was to protect her from hurting herself or her siblings. Other children in the home explained that Melissa was frequently tied up and her mouth was covered with tape to keep her quiet.

A total of five children taken from the home are in protective custody with the Department of Children and Families. Both Stoddards are charged with Aggravated Child Abuse with Great Bodily Harm and are being held without bond.