The head of Nigeria's stock exchange regulator, Arunmah Oteh, has been suspended pending an investigation into allegations of malpractice.
The decision of the regulator's board comes after a parliamentary committee recommended she be investigated.
Ms Oteh was given the job of cleaning up the stock exchange following a crisis in 2009 which saw stocks lose around 60% of their value in a year.
She has not officially been accused of any wrongdoing herself.
The BBC's Will Ross in Lagos says this not the first time a probe into fraud in Nigeria has turned into a circus of accusations and counter-accusations as the hunter turns hunted.
'Yachts and Rolexes'
When she was appointed more than two years ago, Ms Oteh promised to restore credibility in the stock exchange.
She said fraudsters who had caused share prices to collapse would be charged.
Following her suspension by the board of Securities and Exchange Commission (Sec), some analysts believe she is now being punished for treading on some powerful toes, our correspondent says.
"Some powerful people are fighting back," an analyst told our reporter.
Earlier this year at a committee hearing of the House of Representatives into the 2009 crisis, she detailed the alleged financial mismanagement she had uncovered at the Nigeria Stock Exchange.
Ms Oteh outlined incidents of false accounting, misappropriation and questionable transactions.
She said the stock exchange had spent more than $230,000 (£147,000) on a yacht and more than $1m on Rolex watches to be given out as gifts - much of which she said the previous management of the exchange had not accounted for - allegations they deny.
The same parliamentary committee then recommended she be investigated over the alleged mismanagement of funds to mark the 50th anniversary of the stock exchange, which were organised last year by the commission.
Ms Oteh had earlier defended her name at one point accusing the committee of being a "kangaroo court" and the lawmakers of soliciting bribes from her to stop their recommendation - which they deny.
The Sec board says Ms Oteh, who arrived at her office in Abuja on Tuesday morning to find the locks changed, is being sent on "compulsory leave" to allow for an independent investigation into the 50th anniversary allegations.
Her suspension will once again test investor confidence in Africa's second-largest economy, our reporter says.