Prosecutors have searched the home and office of Justice Minister Choo Mi-ae's son to investigate allegations of preferential treatment during his military service in 2017, the prosecution said Tuesday.

The 27-year-old, surnamed Seo, lives in Jeonju, 243 kilometers south of Seoul. The raid took place Monday, according to the Seoul Eastern District Prosecutors Office.

Seo is suspected of getting a special extended leave during his mandatory military service in 2017 thanks to the influence of his mother, who was then the chairwoman of the ruling Democratic Party.

Choo has denied allegations that she or her husband made a phone call to the military to request extended leave for their son following his knee surgery in June 2017.

Seo was on leave from June 5-27, including two successive medical leaves and four personal vacation days. Opposition lawmakers and whistleblowers have alleged that the extensions were granted without following due procedures.

On Saturday, prosecutors also searched the home and office of a captain who served with Seo's unit at the time, as well as the home of a former aide to Choo.

Prosecutors secured their cellphones and are comparing records of past calls and text messages.

Investigators earlier determined that the two spoke at least three times by phone between June 5 and 27, 2017. They are now looking at whether there were additional calls between them and the possible involvement of a third party.

Seo served his military duty in the Korean Augmentation to the United States Army (KATUSA) for the 2nd Infantry Division of the US 8th Army.

The case has become a hot potato in South Korean politics, as issues of fairness are known to rile up the public.

Choo's predecessor, Cho Kuk, stepped down a month after taking office amid a massive public uproar over alleged admissions irregularities and dubious investments involving his family. (Yonhap)