Police believe a 7-year-old boy found dead in a Denver storage unit just before Christmas last attended school in late May.

Denver Police spokesman Sgt. John White said investigators are focused on what happened to the boy between then and Dec. 23, when police found his body after getting information from police in neighboring Aurora.

A woman believed to be the boy's mother, 43-year-old Elisha Pankey, turned herself in to police on Wednesday. She is being held on investigation of child abuse resulting in death.

Online court records do not list an attorney for Pankey.

Formal charges have not been filed yet. The court document laying out the reasons for her arrest is sealed.

Authorities have not confirmed the boy's name or released information about when or how he died.