NEW DELHI: A widening inquiry into diversion of funds and the source of their equity in Jet Airways led to the dramatic detention of Naresh Goyal , founder of the beleaguered carrier, and his wife Anita at Mumbai airport on Saturday.Sources told TOI that the couple was asked to get off the Dubai-bound Emirates flight on the basis of an alert as the Enforcement Directorate is looking into Goyal’s case since the grounded carrier owes over Rs 8,500 crore to lenders, led by State Bank of India .While ED had earlier begun looking at Abu Dhabi carrier Etihad’s investment into a company that ran Jet’s frequent flyer programme for possible violation of FDI norms, the agency is now investigating if funds were routed out of the grounded airline.The ministry of corporate affairs is yet to decide on ordering a probe by the Serious Frauds Investigation Office, although an investigation by the registrar of companies is said to have found lapses, a news agency had reported recently.A probe into the source of Jet’s equity and its investment in other companies can be a complex issue given that there have been multiple questions in the past regarding some of the airline’s early investors.A government official, however, said that the role of banks is not under the scanner at the moment, as Jet was repaying its loans on time until January when a financial crunch at the private carrier resulted in defaults. The defaults prompted banks to step in take control and begin the search for new investors for the private airline that controlled Indian skies for over a decade until Indigo and the now-defunct Kingfisher burst on to the scene.A policeman in Mumbai said there were written instructions to the immigration branch here that Goyal and his wife should not be allowed to leave the country. However, he said there was a mismatch between how the Goyals had spelt their names in their passports and the written government instruction, allowing them to proceed to the aircraft before some officials realised it.Government officials in the Capital said that often, immigration authorities are alerted about lookout notices in the pipeline and they act on the basis of these alerts.“What is the hurry to leave the country? Let us complete the investigations,” said a senior government official.The airline’s liabilities are estimated to be in excess of Rs 20,000 crore, including dues to vendors. Besides, it has defaulted in depositing provident fund money deducted from employees as well as some of the tax it had collected.