Cohen made the admission in a court filing unsealed Friday in Manhattan federal court after a judge earlier this month asked a lawyer to explain how court rulings that do not exist were cited in a motion submitted on Cohen’s behalf. Judge Jesse Furman had also asked what role, if any, Cohen played in drafting the motion.

The AI-generated cases were cited as part of written arguments a lawyer made to try to bring an early end to Cohen’s court supervision after he served more than a year behind bars. Cohen had pleaded guilty in 2018 to tax evasion, campaign finance charges and lying to Congress, saying Trump directed him to arrange the payment of hush money to a porn actor and to a former Playboy model to fend off damage to his 2016 presidential bid.

Cohen, who was disbarred five years ago, said in a declaration submitted to the judge on Thursday that he found the citations by doing research through Google Bard and was unaware that the service could generate nonexistent cases. He said he uses the internet for research because he no longer has access to formal legal-research sources.

“As a non-lawyer, I have not kept up with emerging trends (and related risks) in legal technology and did not realize that Google Bard was a generative text service that, like Chat-GPT, could show citations and descriptions that looked real but actually were not,” Cohen said. “Instead, I understood it to be a super-charged search engine and had repeatedly used it in other contexts to (successfully) find accurate information online.”

He blamed his lawyer and longtime friend David Schwartz for failing to check the validity of his citations before submitting them to the judge, though he asked that the judge dispense mercy toward Schwartz, calling his failure to check the citations an “honest mistake” and “a product of inadvertence, not any intent to deceive.”

Schwartz did not immediately respond to a request for comment.

The bogus citations were discovered by E. Danya Perry, a former federal prosecutor now in private practice who is also representing Cohen in his bid to dissolve his probation early.

“Mr. Cohen engaged in no misconduct and should not suffer any collateral damage from Mr. Schwartz’s misstep,” Perry wrote in her submission to the judge.

In discussing possible sanctions earlier this month, the judge noted that it was the second time this year that a judge in Manhattan federal court has confronted lawyers over fake citations generated by artificial intelligence. Two lawyers in an unrelated case were fined $5,000 for citing bogus cases that were invented by ChatGPT, the AI-powered chatbot.

In entering the 2018 guilty plea, Cohen did not name the two women who received hush money or even Trump, recounting instead that he worked with an “unnamed candidate” to influence the 2016 election. But the amounts and the dates lined up with $130,000 paid to porn actor Stormy Daniels and $150,000 that went to Playboy Playmate Karen McDougal to buy their silence in the weeks and months leading up to the presidential election, which Trump, a Republican, won over Hillary Clinton, a Democrat. Daniels and McDougal claimed to have had affairs with Trump, which he denied.

Trump’s personal lawyer at the time of Cohen’s 2018 guilty plea, former New York Mayor Rudy Giuliani, noted in a statement that there was “no allegation of any wrongdoing against the president in the government’s charges against Mr. Cohen.”