The UK's energy watchdog has suspended a member of staff over the leaking of a list of names of groups who claimed funding from the botched Renewable Heating Incentive (RHI) scheme.
The Belfast Telegraph understands Ofgem is investigating the leak and has reprimanded an employee.
In February, the BBC broadcaster Stephen Nolan revealed he had been given the full list of the 1,946 businesses claiming from the seriously flawed green energy scheme.
He was threatened with legal action from boiler owners to prevent its publication.
Mr Nolan refused to publish the list, saying he "respected the judiciary". A court order was in also place at the time banning the Government from publishing the names.
The PSNI is investigating the leak and is expected to speak to Mr Nolan.
However, the police declined to comment on the matter yesterday.
Ofgem, which regulates the gas and electricity markets, was appointed by the Department of Enterprise, Trade and Investment (DETI) to administer the scheme for a cost of £1.5m.
Asked about the investigation and the suspension, a spokesman for the body said: "We do not comment on staffing issues."
The UK's data protection watchdog will also be probing how the list of names got into the hands of the BBC.
A spokesperson for the Information Commissioner's Office said: "We've received complaints involving the RHI scheme and will be making enquiries."
RHI was intended to encourage people and businesses to switch to sustainable heating systems in order to lessen reliance on fossil fuels.
But a lack of controls meant successful applicants were able to claim more in grants than it cost to run boilers through purchasing wood pellets.
The episode has been described as the biggest scandal since devolution was restored - and played a major role in the recent collapse of Stormont.
Costs quickly spiralled out of control and the botched scheme racked up a projected overspend of almost £500m.
Auditors examined claims that some boiler owners were running their heating constantly with the sole intention of making a profit.
The failure to impose caps was subsequently identified and plans were put in place for new restrictions, but not before a massive surge in the number of applications.
Almost 900 were received in the three months between September and November 2015.
That was almost as many as had signed up to the scheme since it opened in 2012.
Speculation has been intense over who knew the initiative was due to be to closed down and if they encouraged others to sign up before the caps were introduced.
It is not known who was the intended recipient of the leak that Ofgem is currently investigating.
The Department for the Economy, which replaced DETI, later published the names of those businesses which claimed from the scheme after a failed court challenge by an association representing boiler owners to block the list's release.
The department is expected to release a second list of recipients in the coming weeks.
Overall, more than £1bn of public money will be paid to Northern Ireland-based businesses by 2036 after they installed new appliances under the RHI scheme, which is now closed.
Ofgem's role in the scheme, along with all those involved, will be examined as part of the Renewable Heating Incentive inquiry, which is set to open in the autumn.
PSNI Detective Chief Superintendent Tim Mairs said: "As the RHI public inquiry has now commenced, and as we are also in a period of purdah, the PSNI will not be commenting any further on this matter."