Apart from allegations of funding by RAW, the FIA is also probing alleged purchase of arms and money laundering by the party.
Sources within the federal agency said that Merchant, one of the suspects in money laundering case against MQM leaders in London, has been issued a summon to record his statement to the FIA.
The Ministry of Interior has also issued directives to intelligence agencies to share any evidences or information in this regard.
Sources said the decision whether to take up the issue with the British government will be made after the FIA presents its inquiry report.
