Wayne Rooney defied orders from England boss Gareth Southgate to go to bed at the team hotel on Saturday night, according to Sky sources.
The England captain instead stayed up until 5am on Sunday morning and pictures of him drinking at a wedding reception hit the newspapers.
Rooney, 31, apologised "unreservedly" for what he called "inappropriate" images, taken 24 hours after England's 3-0 win over Scotland at Wembley.
FA chief executive Martin Glenn admitted he was concerned by reports that members of England's backroom staff were with Rooney on Saturday night.
Glenn told Sky Sports News HQ: "We're getting a proper investigation of what actually went on. Were there other FA staff involved?
"Obviously it's disappointing, I think it's appropriate that he apologised because it doesn't set a great tone for the England captain, but that said I don't want to over-dramatise it either.
"We're talking to people who were there on Saturday to find out if anyone from the backroom staff were involved and then we will take a view. Why on earth would you be doing that given there is an understanding, a team agreement around alcohol consumption during camp? There will be questions asked for sure."
Asked if the FA will discuss the issue with Manchester United manager Jose Mourinho, who was reportedly furious that England backroom staff were with Rooney, Glenn replied: "No. We'll establish the facts ourselves, it's our camp."
There were also reports that 10 players left the base to attend a night out in central London on Saturday evening, but Sky sources have told us nobody has broken any rules and nobody will be formally disciplined after events over the weekend.