The brother-in-law of former Woori Financial Group Chairman Son Tae-seung covers his face as he appears at the Seoul Southern District Court, Saturday, for questioning over alleged inappropriate loans provided by Woori Bank. Yonhap

A relative of former Woori Financial Group Chairman Son Tae-seung was detained Saturday for allegedly taking out massive, inappropriate loans from the group's banking arm, a court said Sunday.

Identified as Kim, Son's brother-in-law is suspected of forgery and embezzlement in relation to a total of 35 billion won ($26.12 million) that Woori Bank provided in loans to individual business owners and companies tied to the ex-chairman's family members.

"(The court) issued a warrant to arrest and detain the suspect due to concerns of flight risk and potential destruction of evidence," the Seoul Southern District Court said.

The prosecution has been searching Woori Bank's headquarters and branch offices, alleging the bank offered inappropriate loans from April 2020 to January this year.

Prosecutors suspect the bank improperly evaluated loan-related documents and collateral to provide such loans.

With regard to Kim, prosecutors raided his home and office on Aug. 27 before arresting him last week.

The case added to concerns over lax management and financial crimes occurring at the country's banking groups, which, in turn, prompted calls for holding their management liable.

Son headed the group, which controls Woori Bank, from 2020 to 2023. He was succeeded by Yim Jong-yong, who formerly led NongHyup Financial Group.

Woori Bank was repeatedly embroiled in cases of embezzlement and other financial crimes involving its employees.

The financial regulators have been closely monitoring Woori Bank and the group's other subsidiaries for questionable business practices.

The Financial Supervisory Service will launch an inspection against these companies next month.