On Tuesday evening, the Sinn Féin Regional Development minister Conor Murphy said the position of his Permanent Secretary, Paul Priestly, was "no longer tenable".
Within minutes, the Department of Regional Development confirmed that Mr Priestly was suspended "pending an investigation into events following the Public Accounts Committee hearing on NI Water."
"The suspension, in accordance with Northern Ireland Civil Service personnel procedures, is for the purpose of facilitating the investigation and is not a disciplinary penalty".
Mr Priestly, a career civil servant and Northern Ireland Office veteran, has been in charge at the DRD for two and a half years.
He was a key witness at a hearing of the Public Accounts Committee in July.
He was at the heart of a three-month investigation by UTV Business Editor Jamie Delargy into the sackings of Declan Gormley, Ruth Thompson, John Ballard and Chris Mellor from Northern Ireland Water.
The four non-executive directors were fired in March, after an internal audit revealed contracts worth millions of pounds had been improperly approved.
Following the audit, the Department of Regional Development appointed an Independent Review Team to investigate who was responsible for the failings in the organisation.
UTV obtained a trail of emails prompting questions about the independence of the government appointed inquiry.
The programme showed that when the first draft of the Independent Review Team's report was passed to Mr Priestly, he sought to change the wording of some of its findings, a move which diluted criticism of his department and focused blame on the non-executive directors.
The Sinn Fein minister robustly defended his department's role in the investigation, when interviewed by UTV as part of the programme.
'Unprecedented'
However, on Tuesday evening Mr Murphy said: "In light of new information received by me today in a phone call from Paul Priestly, I have spoken to Bruce Robinson, Head of the Civil Service and made it clear that Mr Priestly's position as Permanent Secretary of DRD is no longer tenable."
"I have urged the Head of the Civil Service to properly address this matter and with urgency."
It is believed that Mr Priestly admitted during the telephone call helping draft a controversial letter. At this stage for legal reasons, UTV is unable to reveal the content of this communication.
"We have been aware of it for some time and we believe it was in relation to a communication between Paul Priestly and Peter Dixon of Phoenix Gas", Jamie Delargy explained on UTV Live Tonight.
One of the sacked non-executive directors, Declan Gormley, told UTV Mr Murphy had no choice but to take action.
"I take no pleasure in Mr Priestly's suspension but I think the minister acted to do the right thing, in light of unfolding events," he said.
"I think that the others involved in this episode need to consider their own positions."
With Paul Priestly suspended, attention has now focused on the Minister, who as recently as Monday, was standing by his highest ranking official.
Describing the situation as "political dynamite", Ulster Unionist MLA David McNarry said the unfolding events were unprecedented.
"I think the Minister, having made his position clear about his Permanent Secretary, is going to also now have to answer questions about his position.
"Last night with Jamie Delargy, he said he was in charge, he was responsible - so he is responsible."
John Dallat, an SDLP member of the Public Accounts Committee, told UTV the decision to suspend Mr Priestly was "inevitable".
"What happens now is absolutely vital in terms of the inquiry itself. It must be completely independent and it must focus not just on the Permanent Secretary".
The vice-chairman of the DRD Committee, DUP MLA Michelle McIlveen, has called for a special sitting of the committee.
"There are clearly questions about the independence of the review in light of what has transpired through UTV's investigations and I think a lot of questions will be asked around independent reviews in the future," she said.
"The Minister is ultimately responsible for his Department and this situation did not develop overnight. We have witnessed the sacking of the four non-executive directors and now the Permanent Secretary of DRD has been suspended. This seems like a Department out of control."
UTV's Jamie Delargy confirmed the suspension of one of Northern Ireland's most senior civil servants was "unprecedented".
"The Northern Ireland civil service, I think, has been shaken to the core by this. I don't think it will ever be the same again", he told UTV Live Tonight.