MBK Chairman Kim Byung-ju, identified as the key suspect in the Homeplus fraud investigation, has been banned from leaving the country.

According to KBS on Monday, the Seoul Central District Prosecutors’ Office issued a travel ban for Kim, a U.S. citizen, through the Ministry of Justice.

Kim returned from a business trip to London on Saturday.

Immediately upon his return, the prosecution conducted a raid and seized Kim’s mobile phone and other items.

Homeplus and its majority shareholder, MBK, allegedly sold bonds to individuals and corporations while hiding the fact that the supermarket chain’s credit rating had been downgraded.