A hillside is left scorched by a massive wildfire in Andong, North Gyeongsang Province, Saturday. Yonhap

Police began investigating a 56-year-old man on suspicion of igniting the wildfires that ravaged southeastern Korea over the past 10 days, leaving 30 dead and burning up vast stretches of land.

According to the police on Sunday, the suspect allegedly started the fire around 11:24 a.m. on March 22 while conducting an ancestral rite at a family grave on a hill in Uiseong, North Gyeongsang Province. He has been accused of violating the Forest Protection Act.

The flames quickly spread from Uiseong to nearby areas including Andong, Cheongsong, Yeongyang and Yeongdeok in the province. The fire continued to rage for days, making it the most destructive in the country's history.

The suspect denied the allegations against him, according to police.

When the fire started, the suspect's daughter called the fire service. "A fire broke out, and my great-grandfather's grave is burning," she said. "I came here with my father." Police later confirmed that the suspect's wife was also at the scene.

During preliminary questioning at Anpyeong Police Substation, the daughter explained that they had been trying to remove a tree branch on the burial site.

She told the police that they attempted to burn the branch with a lighter after being unable to break it, but the wind carried the embers, sparking the wildfire.

The police plan to conduct a joint forensic investigation as early as this week, in collaboration with the National Institute of Forest Science, the National Forensic Service and fire authorities, to determine the exact cause and circumstances of the blaze.

The primary blaze of the massive wildfires in North Gyeongsang Province was extinguished around 1 p.m. on Sunday, 213 hours and 34 minutes after it started, according to the Korea Forest Service (KFS).

Acting Interior Minister Ko Ki-dong also made an announcement during a meeting of the Central Disaster and Safety Countermeasures Headquarters that the fires in North and South Gyeongsang provinces have been fully contained after over a week of extinguishing efforts.

Despite the progress, firefighters continued to battle flare-ups in several areas. On Saturday, wildfires reignited in Andong and Uiseong, and in the early hours of Sunday, another fire reignited in Cheongsong around 3:12 a.m., forcing nearby residents to evacuate.

The wildfires, which became the most destructive on record in the country, burned approximately 48,238 hectares — an area roughly equivalent to 80 percent of the nation's capital. The disaster resulted in at least 30 deaths and 45 injuries.

This also became the second-longest wildfire since the KFS began keeping official records in 1986.

The longest was a massive wildfire that erupted on March 4, 2022, in Uljin, North Gyeongsang Province, and spread to Samcheok, Gangwon Province, lasting 213 hours and 43 minutes before being fully extinguished after 10 days.

"This kind of unprecedented wildfire could happen again at any time, so thorough prevention and preparation are essential," Ko said.

He vowed to conduct frequent on-site inspections of high-risk areas and pre-deploy firefighting personnel and equipment for a swift initial response.

"Considering the recent trend of wildfires spreading rapidly, we will establish detailed pre-evacuation plans for residents," he said.