Final answer:
The primary approach in conducting an arson investigation after discovering accelerant on a bed in a house fire would be to collect samples of the accelerant for laboratory analysis and conduct a thorough examination of the fire scene.
Step-by-step explanation:
In conducting an arson investigation after discovering accelerant all over the remains of a bed in the upstairs master bedroom of a house fire, the primary approach would be to collect samples of the accelerant for laboratory analysis and conduct a thorough examination of the fire scene.
Collecting samples of the accelerant will help determine its composition and identify its source, providing crucial evidence for the investigation. Additionally, a careful examination of the fire scene can help identify any other possible causes or patterns that may point to arson.