Singh was questioned for two hours today, Raj Nivas sources said.
The ED team from Mumbai had grilled Singh for five hours yesterday, with the entire proceedings being reportedly video-graphed.
Raj Nivas sources were tight-lipped on whether the questioning, which concluded at 12.30 pm, was video-graphed.
"None of us had any access to the venue where questioning was done," the sources said.
Singh is in the eye of a storm for his action as a Congress Rajya Sabha member in 1997 in recommending expeditious issuance of passport to Khan, a Pune-based stud farm owner.
Singh admitted that he did make such a recommendation on humanitarian grounds as he was told that Khan needed to travel abroad to visit his ailing brother. He however claimed he did not know Khan.
The Lt Governor's name surfaced during questioning of Bihar-based Congress leader Amlendu Pandey.
The ED action followed clearance from the Prime Minister's Office last week to record Singh's statement on the issue.
Singh is also embroiled in another controversy, facing charges that a trust in which his two sons were former members had been given in-principle clearance by the administration to set up a medical college without following due procedures.
Opposition parties have called for a bandh tomorrow seeking recall of Singh, who has however received support from Chief Minister V Vaithilingam.
The Chief Minister said "there is no necessity" for Singh to step down as he was facing only allegations and the ED would do "necessary statutory follow up."
District authorities have clamped prohibitory orders in Puducherry and Mahe regions for today and on Wednesday, April 27 after the dawn to dusk bandh call by CPI(M), AIADMK and BSP.