The Fulton county district attorney prosecuting Donald Trump over his efforts to overturn the 2020 election in Georgia had travel paid for by a special prosecutor she hired for the case and with whom she is alleged to have been involved in an improper relationship, according to a court filing submitted on Friday. Bank records for the special prosecutor Nathan Wade attached as an exhibit to the filing, submitted by Wade’s wife in a divorce proceeding, showed that the district attorney, Fani Willis, was named as a travel companion on at least two trips while the Trump investigation was ongoing. The records could bolster allegations in a recent filing made by Trump’s co-defendant Michael Roman – director of Trump’s 2020 election-day operations – seeking to have Willis relieved of bringing the Fulton county racketeering case against Trump and his allies. The relationship between Willis and Wade threatens to undercut the case because it raises potential conflict of interest concerns that could see the district attorney’s office disqualified for continuing with the prosecution. The transactions from Wade’s credit card statements attached as an exhibit show that Wade paid for at least two trips during the criminal investigation into Trump that named Willis as a travel companion. The first trip, dated 4 October 2022, involves a flight from Atlanta to Miami. Wade paid for a ticket for himself and for Willis. Separately, on the same date and without any names attached, the statement shows Wade’s credit card was used to make two purchases with Royal Caribbean Cruises, for $1,284 and $1,387. The second trip, dated 25 April 2023, involves a flight from Atlanta to San Francisco. Wade again paid for a ticket for himself and for Willis. Separately, on 14 May 2023, Wade’s credit card was used to make two purchases of $612 and $228 with a Doubletree hotel in Napa Valley, California. Roman’s motion claimed Willis personally profited from the contract. Wade was paid at least $653,000 and potentially as much as $1m for legal fees as one of the lead prosecutors on the Trump case, and the filing alleged Wade then paid for trips he took with Willis to Napa Valley and the Caribbean. The motion included no proof of the allegations. Roman’s lawyer Ashleigh Merchant, a respected local attorney who publicly endorsed Wade when he ran to be a Cobb county superior judge 2016, has said the claims were based on sources and records from Wade’s divorce proceeding that remains under seal. Willis has not directly addressed the allegations, and a spokesperson has said the district attorney’s office would speak through its court filings. The allegations are scheduled to be addressed next month after the Fulton county superior court judge Scott McAfee, who is presiding in the Trump case, set an evidentiary hearing for 15 February. The date comes two weeks after the judge in the divorce case holds a hearing on whether to unseal. Wade started divorce proceedings the day after he was hired as a special prosecutor on the Trump case. The divorce turned contentious last year, after Jocelyn Mayfield Wade complained that her husband had failed to disclose his finances, including income from working on the Trump case. The complaint resulted in Wade being held in contempt by the Cobb county superior court judge Henry Thompson and, in January, Willis herself was subpoenaed for information relating to Wade’s work. The subpoena ordered her to sit for a taped deposition on 23 January. On Thursday, Willis accused Wade’s wife of “conspiring with interested parties in the criminal election interference case to use the civil discovery process to annoy, embarrass and oppress District Attorney Willis” in a motion to quash, and sought a protective order to avoid the deposition. The court filing with Wade’s bank records attached as exhibits was submitted by Jocelyn Mayfield Wade’s lawyer on Friday. The Guardian is part of a media coalition to unseal the divorce case and obtained a copy of the reply brief before it was filed on the public docket.