Police in North Gyeongsang Province launched their first joint field inspection on Monday near the starting point of the wildfires in the province that killed 26 people. 

The inspection, which began at 11 a.m. in a hilly area of Uiseong County, saw the participation of the National Forensic Service, the National Institute of Forest Science and firefighting authorities. 

Using drones, the investigators sought to determine what initially caused the wildfires and in which direction the flames spread. 

The investigators also searched the area for any objects that may have caused the wildfire. 

The joint inspection followed an on-site examination on the same hills Saturday, when police retrieved a lighter near a grave mound and took pictures of the damaged grounds. 

On Friday, the police booked a 56-year-old man without detention on suspicion of starting the fire while tending to the grave of his grandparents on March 22. 

The suspect is said to have denied the allegations against him.