The US Department of Justice (DOJ) has opened a criminal investigation into writer E Jean Carroll, who accused President Donald Trump of sexual assault, CBS News, the BBC's US partner, has reported.

The investigation is looking into whether Carroll committed perjury in connection with civil cases she brought against Trump, the news outlet quotes sources as saying.

Carroll, a former magazine columnist, accused Trump of sexual assault and defamation, and successfully sued him in two cases. Both judgements were upheld on appeal, but Trump has since asked the Supreme Court to overturn the first of them.

He has denied the accusations. The BBC has contacted the DOJ and Carroll's lawyer for comment.

In 2023, a jury found Trump liable for sexual assault. He was also found liable for defamation for comments he made the previous year in a post on Truth Social.

In that post, he denied Carroll's claim that she had been attacked by him in the mid-1990s in a New York department store dressing room.

A second lawsuit in 2024 found Trump again liable for defamation in connection with comments he made about Carroll in 2019, in which he accused her of making up the claims against him to sell a book.

Trump has appealed to the US Supreme Court to overturn the first judgement, for which he was ordered to pay $5m (£3.7m) to Carroll. He has also vowed to do the same with the other case, in which Carroll was awarded $83m.

The new criminal case is looking into whether Carroll lied when she said in a 2022 deposition that she received no outside funding for her civil lawsuit against Trump, a source told CBS.

It was revealed in legal papers first filed by Trump's lawyers in 2023 that the co-founder of LinkedIn, Reid Hoffman, had helped to pay for some of Carroll's legal fees and expenses.

The issue was brought up during the case's appeal, and the court found that Carroll had "plausibly represented" in her deposition "that she had forgotten about the limited outside funding counsel obtained".

The "additional discovery... showed that Ms Carroll simply was not involved in the matter of who was or was not funding her litigation costs," the US Court of Appeals for the Second District continued in a 2024 ruling.

The new investigation is being led by the US Attorney's Office for the Northern District of Illinois, one source told CBS.

CNN, which first reported the story, reported that while Carroll's deposition took place in New York, one of the individuals who helped cover some of Carroll's legal fees, Hoffman, has a non-profit organisation based in Chicago.

The BBC has also approached Hoffman's non-profit for comment.

Acting US Attorney General Todd Blanche, who personally represented Trump in the appeal cases against Carroll, is recused from the case, a source told CBS.

Since returning to office last year, Trump has repeatedly called on the DOJ to prosecute a range of his adversaries.

The DOJ also recently created a $1.8bn fund to pay individuals deemed to have been unfairly investigated during the tenure of previous presidents. But some members of Trump's own Republican Party have joined opposition Democrats in condemning the plan.

One of the chief concerns raised by critics is about potential compensation for individuals who assaulted Capitol police officers on 6 January.