The discovery has strengthened investigators' belief that Patricia Wilson, 58, was murdered, deputy prosecutor Patrick Desjardins said.
Blood was also found in the car of Wilson's 50-year-old gardener, with whom she is thought to have been romantically involved.
The gardener was charged with her murder on Saturday but continues to deny any involvement in her disappearance.
The results of tests on the blood found in the car will be available on Tuesday.
The pattern of the blood stains around the property has led investigators to conclude that Wilson was involved in a struggle and that her body was subsequently dragged into a car.
Wilson had been living in the small village of Vabre-Tizac for several years and had begun her relationship with the gardener after separating from
her husband, according to neighbours.