European football governing body UEFA has asked FIFA to investigate whether a critical report on UEFA president Michel Platini was distributed from the office of Joseph Blatter or even written on his behalf.
"We have asked FIFA to investigate the origin of this article because we are concerned by reports of a possible smear campaign against the UEFA president," a UEFA spokesman said, confirming a report in the German newspaper Welt am Sonntag.
A text headed 'Platini: skeletons in the cloest' had been offered by a member of Blatter's staff to Swiss newspapers.
Platini is standing to replace Blatter at a special FIFA congress on February 26, 2016, after the latter pledged to give up his mandate amid the latest corruption scandals surrounding the world governing body.
Blatter and Platini were previously close but relations between the two have become increasingly strained in recent years.
On Saturday Blatter complained in an interview with the Dutch newspaper de Volkskrant that Platini had intimidated his brother at the last FIFA congress in May. Platini is alleged to have said Blatter would go to prison if he did not resign his position as FIFA boss.