NEW : `` I ca n't imagine a mother doing this to a child , '' Sandra Cantu 's aunt says . The woman who was killed in the crash is identified as Jennifer Cantu. Suspect 's daughter was Sandra 's friend , playmate . Melissa Huckaby was arrested on charges of kidnapping and murder , police say . Body of Sandra , 8 , was found Monday stuffed in a suitcase submerged in a pond .
NEW : `` I ca n't imagine a mother doing this to a child , '' Sandra Cantu 's aunt says . NEW : Suspect 's daughter was Sandra 's friend , playmate . Melissa Huckaby was arrested on charges of kidnapping and murder , police say . Body of Sandra , 8 , was found Monday stuffed in a suitcase submerged in a pond .