The brother and business partner of Irish entrepreneur Peter Conlon, who is at the centre of a case involving the alleged misappropriation of €3.8m, said he doesn't know his sibling's current address.
Michael Conlon (68) resigned as secretary of Pembroke Dynamic Internet Services in November last year.
However, documents notifying the resignation to the Companies Registration Office (CRO) were not lodged until January.
The company was behind the Ammado charity fundraising website, which is the subject of the High Court action.
Mr Conlon indicated in the document that he was unaware of his brother's residential address.
"Current residential address not known to me," Mr Conlon wrote under a declaration of current officers of the company.
"I confirm that I have no claim whatsoever of any kind relating to my position as secretary or its termination," he said in a letter to his brother, included in the CRO filing.
There was no one home when the Irish Independent called to Michael Conlon's Dublin home yesterday and he did not respond to calls.
Peter Conlon (63) is understood to be in police custody in Zurich, Switzerland, having been arrested in December.
The missing funds were uncovered and Irish authorities alerted after the Revenue appointed liquidator Myles Kirby, of Dublin firm Kirby Healy, to recover approximately €400,000 in unpaid taxes from Pembroke Dynamic Internet Services on January 22.
Rossa Fanning, SC for the liquidator, previously told the High Court that Mr Conlon had “gone to ground” and has been uncontactable.
Irish charities including Trócaire and Concern, along with hundreds of international organisations, were signed up to use the Ammado fund-raising website.
"It would appear that at least 800 charities may be affected by the liquidation of the company, which is connected to the Ammado Foundation," according to a letter on behalf of the liquidator.
It is understood investigators are looking into assets held by Peter Conlon in Malta, Belgium and the Isle of Man.
He attempted to find new financial backers as recently as December 6.
He circulated a prospectus that claimed Ammado Technologies had no debts and owned valuable intellectual property, despite the main related trading business being on the brink of collapse by that point.
The High Court heard last week that there was currently just €357,000 in the company's bank account.