A female member of Donald Trump's family was involved in decisions over how to handle classified US government documents that he took from the White House, prosecutors have said. In a historic indictment unsealed on Friday, authorities alleged that an unnamed family member gave instructions to Mr Trump's aide Walt Nauta as he was preparing to squirrel away documents that the former president did not wish to give back. The accusation widens the circle of people who may have had unauthorised influence over sensitive information about US nuclear weapons, military plans, foreign relations, and more. Yet the identity of the family member remains a mystery, with the only clue being that Mr Nauta allegedly addressed her as "ma'am". ABC News reported that the woman was likely to be Mr Trump's wife Melania, citing inside sources. Melania Trump's office did not immediately respond to a request for comment. Mr Trump is facing 37 criminal charges including willfully retaining national defence information, conspiracy to obstruct justice, concealing a document in a federal investigation, and false statements and representations. Prosecutors claim that Mr Trump schemed to keep hold of some documents in defiance of a legal order to give them back, while storing them insecurely at his Mar-a-Lago estate in Florida while tens of thousands of guests came and went. Mr Trump contends that he is "an innocent man" and that the charges are "a hoax" contrived by his political enemies. According to the indictment, Mr Trump's family member became involved on 30 May 2022, just day before a lawyer was due to search his storage room for classified documents demanded by the government. Before that happened, Mr Trump allegedly asked Mr Nauta to remove 64 boxes from their storage room and bring them to his private residence, meaning they would not be present for the lawyer to search. That day, the family member allegedly texted Mr Nauta: "Good afternoon, Walt. Happy Memorial Day! I saw you put boxes to POTUS' room. "Just FYI, and I will tell him as well: not sure how many he wants to take on Friday on the plane. We will NOT have room for them. Plane will be full with luggage. Thank you!" Mr Nauta replied with a smiley face emoji, saying: "Good afternoon ma'am. Thank you so much. I think he wanted to pick from them. I don't imagine him wanting to take the boxes. "He told me to put them in the room and that he was going to talk to you about them." The indictment says nothing more about who this family member might have been, how much she knew about the documents, and what her intentions were in texting Mr Nauta. The most prominent women in Mr Trump's immediate family are his wife Melania, his daughter from his first marriage Ivanka, 41, and his daughter from his second marriage Tiffany, 29. The indictment does not suggest that any of them had knowledge of any illegal behaviour. Read More Trump bragged a ‘secret’ document ‘totally wins my case’. A tape of his remarks could land him in prison Trump news — latest: Trump ‘plotted to hide documents from FBI after showing military docs to visitors’ Hiding documents from the FBI and foreign nuclear plans: Key allegations in Trump’s unsealed indictment