[4] He allegedly stashed away billions into Swiss bank accounts with the help of Kolkata-based businessman Kashinath Tapuriah and Delhi-based Praveen Kumar using hawala.
[13] In March 2007, Hasan Ali's properties were raided by India's Enforcement Directorate (ED) and Income Tax officials based on allegations of hawala transactions.
Allegedly, in 2003, Khan helped launder US$300 million of money Khashoggi made through arms sales through the Zurich branch of Swiss bank UBS.
[21] However, the Swiss bank UBS denied Indian media reports alleging that it maintained a business relationship with or had any assets or accounts for Hasan Ali Khan accused in the $8 billion black money case.
Upon formal request by Indian and Swiss government authorities, the bank announced that the documentation supposedly corroborating such allegations was forged and numerous media reports claiming $8 billion in stashed black money were false.
[22][23] India Today, in a later article, wrote, "Hasan Ali Khan stands accused of massive tax evasion and stashing money in secret bank accounts abroad.