Barbadian Lisle Austin, appointed interim president on Monday in place of suspended Trinidadian Jack Warner, moved quickly by issuing Blazer with a demand to explain himself and to stop working with the U.S. lawyers who presented evidence against Warner.
It was Blazer's report to FIFA's Ethics Committee, which included allegations of bribery against Warner and Asian football chief Mohammed Bin Hammam of Qatar, that led to this week's explosion of accusations and counter-accusations at world football's governing body in Zurich.
In a letter to Blazer seen by Reuters, Austin gave the American 48 hours to explain by what authority he appointed Chicago-based lawyers Collins and Collins to conduct investigations into the members of CONCACAF, the Confederation of North, Central American and Caribbean Association Football.
The letter also asks Blazer to produce minutes or documentation to show the decision was taken by the confederation's executive committee and to stop Collins and Collins from "conducting any business" including legal advice or representation for CONCACAF.
Lawyer John Collins has had a long-standing relationship with CONCACAF and with the U.S. Soccer Federation.
Blazer was not immediately available for comment but the letter indicates the new post-Warner CONCACAF is unlikely to make a harmonious start.
On Sunday FIFA's Ethics Committee suspended Warner and Bin Hammam pending full investigations of the charges made by Blazer.
A report by FIFA Executive Committee member Blazer said there had been possible violations of the FIFA ethics code in a meeting between Caribbean officials, Warner and Bin Hammam in Port of Spain this month.
Bin Hammam, who has now withdrawn his bid to take on incumbent Sepp Blatter in this week's FIFA presidential election, and Warner denied any wrongdoing.
On Monday FIFA Secretary General Jerome Valcke produced an email from the president of the Puerto Rico Football Association who stated he had been offered a $40,000 inducement, which he accepted, reported and was sending to football's governing body.
