South Korea's tax agency and prosecutors have launched an investigation into suspicions that assets of former President Chun Doo-hwan might be concealed in diverse insurance products under the names of his family members, relatives and close aides, industry sources said Thursday.

The probe is part of intensifying efforts by the government to find concealed assets of the former president who was ordered by a court in 1997 to return to the state coffers the 220 billion won (US$196.8 million) he was found to have accumulated during his presidency in the 1980s.

He has so far paid only a quarter of the total, with some 167.2 billion won remaining unpaid. He refused to make the payment, saying he was nearly penniless.

According to the sources in the insurance industry, the National Tax Service and the Supreme Prosecutors' Office recently made official requests for five major insurance companies to provide information and data related to any contracts that they had signed with Chun's family members, relatives and close aides.

The insurance companies are Samsung Life Insurance, Samsung Fire and Marine Insurance, Kyobo Life Insurance, Shinhan Life and Hanwha Life Insurance, the sources said.

Some of them have already provided the requested information to the tax agency and prosecutors, which subsequently started to work on tracing back the exact routes of money flows tied to the involved insurance products, other sources said.

The move comes after state prosecutors and tax authorities raided the residence of the former president in Seoul along with the offices and homes of his eldest son and other close relatives to secure properties and documents that could help their investigation.

The investigation into Chun's assets has been gaining traction recently since the National Assembly passed a bill in June aimed at extending the statute of limitations on forfeiting and imposing fines on public officials' illegal wealth from three years to 10.

Under the revised law, Chun will be required to pay the remainder of his fines by October 2020, not October this year. (Yonhap News)