SEOUL, South Korea — After North Korea blew up an inter-Korean liaison office on its own soil last month, plunging relations with South Korea to a diplomatic nadir, a conservative activist lawyer in the South decided that one person was responsible: Kim Yo-jong, the only sister of North Korea’s leader, Kim Jong-un.
So he filed a lawsuit against Ms. Kim.
South Korean prosecutors said on Friday that they were looking into the litigation, but it was not clear whether they would begin a formal investigation. Their hands appeared to be tied: They have practically no way to summon Mr. Kim’s sister to court to face the accusation.
The suit is largely symbolic, but if it triggers an angry reaction from the North, it could lead to the further deterioration of the relationship between the two Koreas.
The activist lawyer, Lee Kyung-jae, a vocal critic of Moon Jae-in, South Korea’s president, told reporters last week that he had been driven to file the lawsuit in part because the government of Mr. Moon had not been aggressive enough in dealing with the North’s destruction of the liaison office.
Inter-Korean relations were warmer in 2018, when Mr. Kim held summit meetings with President Moon, who helped arrange meetings between Mr. Kim and President Trump. But ties turned frosty once Mr. Kim’s second meeting with Mr. Trump, held in Vietnam in February 2019, collapsed.
Tension mounted between the two Koreas as Ms. Kim became the hard-line face and voice of North Korea. After activists in the South sent anti-North Korean leaflets over the border into the North, she issued a series of statements threatening retaliation — including the destruction of the liaison office.
The North Korean military did blow up the office last month, which is in the border city of Kaesong, North Korea. But her brother later suspended any further military actions aimed at scuttling the relatively warm relationship that had developed between the two Koreas in recent years.
Last week, Mr. Lee filed the lawsuit asking prosecutors to indict Ms. Kim, along with Pak Jong-chon, chief of the general staff of the North Korean military, on charges of destroying a building constructed with South Korean taxpayer’s money.
A legal complaint in South Korea is generally assigned to a prosecutor to decide whether it merits a full investigation. Prosecutors usually suspend attempts to indict criminal suspects when they cannot be brought to court. Even Mr. Lee acknowledged that there was no way for prosecutors to present Ms. Kim in a court in the South.
The lawsuit against Ms. Kim comes on the heels of a landmark ruling this month in a civil suit filed on behalf of two South Korean prisoners of war from the 1950-53 Korean War. With the help of conservative lawyers, the men, who spent decades in the North before escaping to the South, won their case when a Seoul court ordered Kim Jong-un and North Korea to compensate them for the forced labor they suffered while in the North.
Under South Korea’s Constitution, North Korea and its people are technically part of South Korea. And in South Korea, civil lawsuits can be tried without the defendants in court. The ruling in the P.O.W. case ruling was also largely symbolic because there was no way South Korea can force Mr. Kim and North Korea to pay the compensation.
Still, it encouraged politically active conservative lawyers to file or consider other lawsuits against North Korea over a host of issues, such as the widespread abuse of human rights.
Prosecutors have yet to decide whether to seek criminal charges against Ms. Kim. But given past practices, they will most likely drop the case after studying the complaint.
In the past, activists had sued top North Korean leaders, like Mr. Kim’s father, Kim Jong-il, over incidents like the sinking of a South Korean navy ship in 2010. But prosecutors indicted no one.