An unidentified hacker has gained access to a computer file shared in a secure link among lawyers whose clients have given damaging testimony related to Matt Gaetz, the former Florida congressman who is President-elect Donald J. Trump’s choice to be attorney-general, a person with knowledge of the activity said.

The file of 24 exhibits is said to include sworn testimony by a woman who said that she had sex with Gaetz in 2017 when she was 17, as well as corroborating testimony by a second woman who said that she witnessed the encounter.

The files were downloaded by a person using the name Altam Beezley at 1.23 pm (local time) on Monday, according to the person, who was not authorised to speak publicly. A lawyer connected to the case sent an email to the address associated with Altam Beezley, only to be informed in an automated reply that the recipient does not exist.

The material does not appear to have been made public by the hacker.

The documents include information that is under seal with the justice department, which investigated Gaetz but did not file charges, and the House Committee on Ethics, which has completed its own inquiry into the former congressman. The Ethics panel’s members are scheduled to meet on Wednesday to decide on whether to vote to release material it has gathered.

But the hacked trove of documents stems from an altogether different source: a civil suit being pursued by a friend of Gaetz’s, Christopher Dorworth, a Florida businessman. Dorworth filed the suit against both the woman who says she had sex with Gaetz when she was a minor and Joel Greenberg, an erstwhile ally of Gaetz who is serving an 11-year prison term after pleading guilty to sex trafficking charges involving the woman.

Dorworth has claimed that he was defamed by Greenberg and the woman, both of whom had told federal authorities that Dorworth hosted parties where he, they, Gaetz and others took drugs and openly had sex.

In mustering their defence, lawyers for Greenberg and the woman have solicited sworn statements from others who they say were witnesses. The 24 exhibits were attached to a motion prepared by lawyers for Greenberg and the woman in response to Dorworth’s suit.

In addition to the depositions from the woman who was a minor at the time of the encounter and the woman who said she was a witness, the hacked information also includes sworn testimony from Dorworth and his wife, as well as testimony from Michael Fischer, Gaetz’s former campaign treasurer, who is also said to have attended the party.