Sepp Blatter has urged Michel Platini to join forces with him in a battle against the suspensions imposed on the pair by FIFA.
Platini had appeared set to succeed Blatter as the head of FIFA when revelations of a "disloyal payment" from Blatter emerged in 2015.
Gianni Infantino, Platini's former general secretary at UEFA, instead replaced Blatter who, with Platini, was given an eight-year ban from football activities that was later reduced on appeal.
Blatter's call comes following revelations about Infantino's connections in the Swiss justice system.
On Wednesday, the Grand Council of the Swiss canton of Valais authorised an investigation into the relationship between Infantino and regional chief prosecutor Rinaldo Arnold.
Mediapart reported that Infantino had used his connections with Arnold to obtain information about the investigation by Switzerland's Public Ministry of the Confederation (MPC) into allegations of corruption at Blatter's FIFA that was opened in September 2015.
It is alleged Infantino met the MPC's chief, Michael Lauber, twice in spring 2016, shortly after winning the election to succeed Blatter that followed the bans imposed on him and Platini.
"I think Michel's lawyer should contact mine. We have to go on together now, our destinies are linked," Blatter told L'Equipe.
"I'm on the attack. I spoke to my lawyer on Tuesday evening. With Platini, it's necessary we unite our forces, because it is after this procedure opened against me that our suspension from the FIFA ethics committee came."
In May, Le Monde reported that Platini was not part of the penal case being pursued by Swiss authorities against Blatter regarding the payment of two million Swiss francs to Platini in 2011.
"Now, we can apply pressure a bit," Blatter said. "With these new revelations, I hope we can finish up with this matter. And if the case is liquidated, the suspension by the Ethics Committee will no longer have any value."