The leader of the main opposition Democratic Party, Lee Jae-myung, said the current administration's conduct toward former President Moon Jae-in and first lady Kim Jung-sook constitutes political retaliation. 

On a visit to Moon's private residence in Yangsan, South Gyeongsang Province, Sunday, Lee said the prosecution's investigation of the Moon family is part of the Yoon Suk Yeol administration's efforts to unite its “handful of supporters.”

According to Lee's chief spokesperson, Jo Seoung-lae, the former president intends to fully cooperate with the investigation.

The state investigative agency is looking into allegations that Moon's former son-in-law unfairly gained employment as an airline executive, in exchange for favors for the company's founder.