Trump allies believe someone may have "flipped" and informed on Trump to the FBI, Axios reported.
The FBI raided Trump's Mar-a-Lago resort on Monday.
Trump's lawyer claims he has fully cooperated with the FBI and the raid was unwarranted.
Allies of Donald Trump believe that an aide or aides to the former president may have "flipped" and provided evidence to the FBI about what he was keeping in his Mar-a-Lago resort in Florida, Axios reported.
According to the report, people close to Trump are filled with paranoia after the FBI raid Monday on the resort Trump has made his home since leaving the White House.
Per Trump's camp, the search was for documents Trump brought to Mar-a-Lago from the White House when leaving office, an issue which prompted previous complaints from the US National Archives.
Trump's lawyer, Christina Bobb, told The Washington Post Tuesday that his legal team had a discussion earlier in the year with Department of Justice lawyers about material being kept in a Ma-a-Lago basement.
The lawyers searched several dozen boxes of items in the basement, she said, and asked that they be better secured.
According to the Post's sources, the raid was focussed on whether Trump withheld items that were earlier requested by the DOJ.
Bobb's claims were echoed by Trump's statement Tuesday in which he said that he had fully cooperated after the National Archive and DOJ had requested that he return items taken from the White House.
Under federal law, records and other material from presidents as part of their official duties must be handed over to the National Archives when they leave office.
After their raid Monday, agents took with them 12 boxes from Mar-a-Lago and Trump claims they broke into a safe.