Infantino wrote to all 211 Fifa member associations saying they would receive $40m (£30m) if they backed his controversial proposal, setting a deadline of 19 September if they wanted to access an initial $20m (£15m).
Thrive Eternal was expected to lead the proposed investor group for FFE.
Thrive is an American venture capital firm founded by Joshua Kushner – the brother of US President Donald Trump’s son-in-law Jared.
Uefa’s request for all documents regarding the investment plan, included “email, instant messages (WhatsApp, Signal, Teams, Slack or any other platform), SMS, written correspondence and meeting notes”, and those which involved “any Fifa officer, employee, committee member, consultant or agent, or any Fifa member association, confederation, broadcaster, sponsor, or financial institution”.
In reference to the 19 September deadline, Uefa added it wanted documents to be retained “relating to the payment structure for Fifa member associations, including the design, modelling, legal basis, approval and communications to member associations”.
Uefa asked Infantino to acknowledge receipt of its letter in writing within five business days, to confirm he had “received and understood this notice” and that he has “taken immediate steps to preserve relevant materials as required”.
Uefa vice-president Laura McAllister described the prospect of legal action by European football’s governing body as “a very clear call for action really for what’s been an abysmal governance process leading up to the FFE initiative”.
Speaking to BBC Radio 5 Live, she added: “We need to learn from this disastrous process to make sure that we have accountability chains in hand to ensure that it doesn’t happen again.”
She hopes others will follow in withdrawing their support for Infantino in what “is a big moment in the history of football”.
“We cannot keep putting out fires because of unilateral plans,” said McAllister.
“I really hope now that we can have a change of leadership next year.”
As the pressure grows on Infantino with Serbia, Sweden and Finland also withdrawing their support, Qatar, Lebanon, Kuwait and Sri Lanka have pledged their support for his Fifa leadership to continue.
Uefa has 55 votes, Africa 54, Asia 46, Concacaf 35, Oceania 11 and Conmebol 10.
The Asian Football Federation (AFC) has said it stands in “solidarity” with Uefa and Concacaf, while Africa, Conmebol and Oceania have not criticised Infantino’s plan.
However, the Fifa Council could try to force Infantino to resign through an emergency meeting.
That would be triggered if 19 of the 37 Fifa Council members call for one and the meeting must take place within two weeks.
Uefa has nine members, AFC has seven, Concacaf five, Africa has six, Conmebol five and Oceania three. It is completed by Infantino and secretary general Mattias Grafstrom.