GREEN RIDGE, Mo. (AP) — A western Missouri sheriff says a house fire earlier this week was deliberately set to hide a double homicide.

The bodies of 56-year-old Barbara Hudson and her 26-year-old son, Jeremiah Hudson, were discovered Monday in their fire-damaged home near Green Ridge, west of Sedalia.

Pettis County Sheriff Kevin Bond says authorities know how the two died but are withholding the information as part of the investigation. No arrests had been made as of Friday.

Bond also declined to say how the fire was set except that it was intentional. He said doors to the house were locked, making burglary appear unlikely.

More than 40 investigators with the Missouri Rural Major Case Squad are working on the case.