Vlassis Kambouroglou was the managing director of Drumilan International, which was involved in the sale of a Russian-made TOR-M1 missile system to Greece.
Kambouroglou was called to testify before a parliamentary inquiry into the arms deal in 2004 but denied that his company made any money from the deal. No charges were brought against him.
However, Tsochatzopoulos’s cousin, Nikos Zigras, who is a key suspect in the graft case, claimed during questioning by prosecutors earlier this year that Kambouroglou was involved in bribing the ex-minister.
Authorities in Indonesia said it was not immediately clear how Kambouroglou had died.