Sources privy to the development said Indian authorities will soon communicate with Switzerland seeking a 'final data' of sorts about the purported bank accounts and transactions of Khan and his associates in the banking channels of that country which investigating agencies claimed to have unearthed earlier.
They said some financial documents linking Khan to a global arms dealer will be sent for "validation" to Swiss authorities as the transaction channels reportedly pertain to using the bank routes of the Alpine nation.
"Some information relating to a bank transfer of USD 800 million in accounts and its routing to various other accounts are pending for some years now. The biggest help of the Swiss authorities is required in getting to the bottom of this particular instance," they said.
"The agencies, post the recent successful meeting the two sides, are very hopeful to take the case forward which has been stuck for want of crucial information for the last two-three years," they said.
Sources said the Special Investigation Team (SIT) on black money is also keen to initiate legal action and achieve finality in this case as Khan's alleged tax evasion probe is the only one issue mentioned by name in the Terms of Reference or working directives of this high-powered panel.
"The SIT has issued directions to the I-T department and Enforcement Directorate to get in touch with Swiss authorities for information in this specific case so that penal proceedings can begun in quick time. The money laundering case against Khan is pending trial in a Mumbai court since 2011," they said.
The SIT, they said, has already decided to put on fast track the alleged tax evasion and laundering of funds case against the 60-year-old businessman.
Agencies including Income Tax, Enforcement Directorate and the Economic Offences Wing of the Mumbai Police have already filed their complaints of alleged tax evasion against Khan.
Recently, a three-member team of Indian revenue department officials held a meeting with their Swiss counterparts in Berne to chalk out future cooperation strategies and initiate better coordination in this area.
The visit is seen as successful and one which will give boost to India's efforts on cracking down on black money stashed abroad and illicit funds hoarded in dubious bank accounts overseas including in Switzerland.
The Terms of Reference framed by the Government for the specially constituted SIT headed by former Supreme Court Judge M B Shah mentions Khan's case as an important one to be dealt with.
"All issues relating to the matters concerning and arising from unaccounted monies of Hasan Ali Khan and (his aide Kashinath) Tapurias," it had said.
The businessman, who is under arrest, came under scrutiny from multiple agencies in 2007 which had been probing him and his associates for various charges of money laundering, income tax evasion and violations of the Passport Act for the last seven years.