(IDEX Online) - Prosecutors have launched an investigation into Eurostar Diamond Traders, one of the world's biggest traders until its collapse in 2019.The Antwerp-based company reported a $16bn turnover in 2016 but was declared bankrupt three years later, with bank debts of $560m.The investigation will focus on possible mismanagement surrounding the bankruptcy, in particular the role of the Dutch state-owned bank ABN AMRO, according to the Brussels Times newspaper.It says investigators will also look into possible breaches on the laws on banks taking part in inventory financing of diamonds, and diamond trading.Eurostar Diamond Traders was founded in 1978 by Kaushik Mehta (pictured), who built a rough diamond polishing empire, with subsidiaries in New York, Shanghai, Botswana, Hong Kong, the UEA and India.