Margaret Sanders is mother of the murder victim Charlie Sanders. Booth visits her and learns that Margaret has two other foster sons, Shawn and David Cook, but Charlie was her only biological child. When Brennan finds a hereditary genetic defect on Charlie's bones, Booth and Brennan confront Margaret with this information and learn that she is not Charlie's biological mother as she claimed. Margaret tells them she took Charlie to save him from the foster care system after his mother died of a drug overdose, but did not have anything to do with his abduction and death. In the end Booth arranges for Margaret to return to Shawn and David.