A visiting Brazilian attorney who was working at Gibson, Dunn & Crutcher in the US has been charged with insider trading for buying and selling shares of a company represented by the law firm.

Romero Cabral Da Costa Neto was charged by the US Attorney for the District of Columbia with using confidential information trading on deals including Swedish Orphan Biovitrum AB’s acquisition of CTI BioPharma Corp. earlier this year. The 33-year-old was also sued by the US Securities and Exchange Commission, which identified the companies involved in the deal.

Authorities said Costa purchased 10,400 shares of CTI BioPharma on May 9, and then sold them a day later after the deal was announced for a profit of $42,649. Costa wasn’t assigned to the transaction, but allegedly accessed files related to the deal more than 100 times.

Costa was a lawyer in Brazil who had been working in the US as a visiting attorney since September 2022.

“We are cooperating with authorities and have terminated our relationship with the individual, who was an international visiting attorney from another law firm,” a spokesperson at Gibson Dunn said in a statement.

Costa was arrested Tuesday in Washington, DC, by agents with the FBI’s Washington Field Office. An attorney for Costa couldn’t be located to comment on the charges.

Prosecutors said that Costa also made trades on at least two other deals involving companies represented by the US law firm, making about $9,500.

If convicted, Costa faces as long as 20 years in prison, according to prosecutors.

--With assistance from Patricia Hurtado.

(Updates with maximum prison sentence)