Long before he became Donald Trump’s feared attack dog, or began to visit the White House as the president’s personal attorney, or took a position with the Republican National Committee, or partnered with powerhouse lobbying firm Squire Patton Boggs, Michael Cohen ran a small legal practice in Hell’s Kitchen.

He was a one-man show and handled a little bit of everything, from personal injury cases to a Ukrainian investment fund to a fleet of taxis to a trust account he managed for clients.

One day in 1999, a check for $350,000 was deposited into that trust account, to be disbursed to a woman living in South Florida. As the lawyer in charge of the account, Cohen was supposed to ensure that she got the money.

But he didn’t.

Why not? And what ultimately happened to all that money?

“I don’t recall,” Cohen said in a deposition.

The missing $350,000 — which has never been recovered — became the centerpiece of a 2009 lawsuit in Miami, where Cohen was accused of civil fraud. After years of litigation, Cohen prevailed, in part because the suit was filed past the statute of limitations.

Cohen, in an interview with BuzzFeed News, said he was first questioned about the money eight years after it was deposited, by which time he said he could not recall much about it. “I honestly don’t remember who gave me the deposit at the time,” he said. “This is another poor attempt to malign my impeccable reputation and attempt to connect me to a Russian conspiracy.”

But Cohen’s own testimony in the case reveals that the man who is now the president’s personal lawyer failed to execute one of the core duties of an attorney — properly handling money placed in his trust — and was cavalier about that failure.

“One of the things lawyers are most likely to be disciplined for is misusing clients’ funds,” said Deborah Rhode, a legal ethics expert from Stanford University, who said that properly accounting for and disbursing funds is a critically important obligation for many attorneys.

“A lawyer who, incident to his law practice, comes into possession of funds belonging to a client (or third person), has very clear obligations,” Stephen Gillers, a professor at New York University, wrote in an email. Like Rhode, he declined to comment on the particulars of Cohen’s case, which he was not familiar with, but said that in general a lawyer “may not commingle the funds with his own. He must keep them in a separate account, sometimes called an escrow or special account. He must ‘promptly’ notify the client or third person of his receipt of the funds and ‘promptly’ deliver them.”