It began just before 7 o'clock Saturday morning when someone called 911 to report a fire at 125 S. Chickamauga Street in Colby. After entering the home, rescuers found the woman inside.
She was transported to Citizens Medical Center where she later died. The department says the investigation is ongoing and more information will be released later.
The KBI, along with the Thomas County Sheriff's Office, State Fire Marshal's office and the Kansas Highway Patrol are assisting in the investigation.
The Colby Free Press was first to report on the incident. Posters to their Facebook page indicate the woman's young daughter was reported mising, but later located, along with a possible suspect.