Investigators found the drug in the grinder Helena Asheim kept in her house in Tranby, just outside Oslo. The same substance has been detected in the body of her ex-husband Per Gunnar Asheim.
Police found Asheim dead on the 27th March, after a passing hiker reported finding the burnt-out car in a parking lot in the village. His ex-wife, who has always denied guilt, was arrested and charged the next day.
According to VG, police still do not know for sure whether 57-year-old businessman was alive or not when the car caught fire.
The wife's bank statements show that she bought matches and a can of diesel in the days before her husband's death.
The couple had been in the middle of a custody battle over their two children.