There are several solid reasons the state prosecution should conduct a fair and thorough investigation of the allegations surrounding Rep. Sohn Hye-won.

Most of all, the scandal smacks strongly of a typical case of conflict of interest. At the core of the case is that people close to Sohn, a member of the National Assembly Culture Committee, massively purchased properties in an old town in the southwestern port city of Mokpo.

The property purchases – totaling as many as 25 – took place before and after a district in the old center of the city was designated as a “cultural heritage site” last August. The designation paved the way for the central and local governments to set aside 110 billion won ($97.6 million) to redevelop the area. About half of the budget comes from the Cultural Heritage Administration, which is audited by the culture committee of the parliament.

The key suspicion here is that Sohn could have used her influence to acquire information about the designation prior to its announcement, or pressure government officials to make the designation. Sohn was an active promoter of the redevelopment project of the old town center of Mokpo, having commented on the need to revive the district several times in parliamentary sessions.

Sohn, who relinquished her ruling party membership in the wake of mounting public criticism, denied allegations that she was looking to profit improperly from the investment and insisted that she only had “goodwill” toward the project. She said she wanted to draw more people to the work to preserve the area as a cultural heritage site and redevelop it into a new town hub that attracts visitors.

But the way the questioned real estate transactions were made points to the possibility of profit-seeking investment.

For instance, one of Sohn’s nephews who bought a guesthouse along with the children of two associates of the lawmaker was serving in the military at the time of the purchase. This was clarified by none other than the nephew’s father.

There are more signs of that a quick profit was Sohn’s true motive. Sohn said she borrowed 1.1 billion on her facilities in Seoul and donated 700 million of the money to a cultural foundation in which her husband is registered as chairman. The foundation spent the 700 million to buy parts of the properties in the cultural heritage area.

This runs counter to common sense. Few people would borrow money to donate to a foundation or good cause. You borrow money when you see investment opportunities. Moreover, Sohn said that she established the foundation, which indicated that her husband was only its nominal head and she is its real owner. Her husband said he never went to Mokpo and his wife took care of all the property transactions involving the foundation.

This raises suspicions that some of the other money spent to purchase properties in the area actually belonged to Sohn. In fact, Sohn have brought in people only who are close to her for the transactions – nephews and children and husband of her associates.

Another reason the prosecution should make a thorough investigation of the allegations involving Sohn is her close ties to President Moon Jae-in and first lady Kim Jung-sook.

Sohn went to the same middle and high school as the first lady. Sohn, a designer and publicity specialist by training and profession, also worked as the chief of the publicity team for Moon’s presidential campaign in 2017.

Na Kyung-won, floor leader of the main opposition Liberty Korea Party, raised suspicion that Sohn’s influence was in part based on her close relationship with the first lady.

Both Na and Sohn Hak-kyu, leader of the minor opposition Bareunmirae Party, said that due to Sohn’s close ties to the president and the first lady, the prosecution may be unable to get to the bottom of the scandal.

Given the current relationship between the ruling camp and the state prosecution, the opposition leaders are right to have such doubts. They are also right to assert that parliamentary investigation or a special probe by an independent counsel may be inevitable eventually. All this will depend on how the prosecution investigation goes.