Wilson, who is in her 60s, moved into the house near the village of Vabre Tizac, between Montpellier and Toulouse, along with her husband about five years ago. The couple split up a little over a year ago, neighbours say.
On Tuesday a neighbour noticed that the shutters were open and Wilson’s car parked in front but that there was no sign of the occupant. After noticing blood stains inside, she called the police.
The gendarmes have not yet established whether it was Wilson’s.
They have sealed the house’s doors and declared the disappearance “worrying”, local papers report.
Divers have been sent to search for a body in the numerous lakes in the hilly area.
A suspect was detained and transferred to Montpellier on Saturday, a judicial source told the AFP news agency.