The North Gyeongsang provincial police department said the unidentified man may have used fire to clear overgrown grass at a family grave on a hill in the southeastern town of Uiseong, one of the areas hardest hit by the wildfires.
Police investigators examined the grave site on Monday and plan to question the man soon.
The police department did not immediately say whether others would also be questioned over suspected links to the wildfires, which fire officials believe may have been sparked by multiple human errors, also including burning trash and sparks from welding work.
Fueled by dry and windy conditions, the wildfires raged for a week, destroying thousands of homes, and leaving mountains covered in ash, before firefighters, aided by rain, brought them under control on Friday.
The 30 people killed were mostly in their 60s or older.
They include a pilot whose helicopter crashed during firefighting efforts and four firefighters and other workers who died earlier after being trapped by fast-moving flames.
At least 45 people were injured, including nine seriously.
The fires damaged or destroyed more than 6,000 structures, including over 1,000 homes each in the southeastern city of Andong and the nearby coastal town of Yeongdeok, as well as more than 330 homes in Uiseong.
The fires in Uiseong damaged about 20 of the 30 structures at the Gounsa temple complex, said to have been originally built in the seventh century.
Among them were two state-designated “treasures,” a pavilion overlooking a stream that dates to 1668 and a Joseon dynasty structure built in 1904 to mark the longevity of a king. (AP)
