Fifa's secretary-general Jerome Valcke has confirmed the authenticity of a document that is at the centre of a police investigation into forgery in Nigeria.
The Force Criminal Investigation Department (FCID) in the Nigerian capital Abuja is investigating forgery allegations against the board of the Nigeria Football Federation (NFF), led by president Alhaji Aminu Maigari.
However the the FCID has rejected Valcke's letter, insisting that Fifa president Sepp Blatter, whose signature is being questioned should, have written to clear the air instead.
The probe centres on documents the NFF used in court, purportedly from Fifa, to defend a case brought by the National Association of Nigerian Footballers (NANF).
The NANF's original case questioned the legality of the NFF elections held in August 2010.
Last week the NANF gave documents signed by Blatter, which do not tally with the one used by the NFF in court last year.
This led to members of the NFF board being detained and later released on bail after answering questions over the allegations.
The NFF is expected to return to the FCID later this week where the police will consider the latest findings before deciding if there are grounds for trial.
A top NFF board member insisted to BBC Sport that they are confident the 'little storm' will not lead to a trial as the letter in question is authentic.