The federal authorities arrested a Treasury Department official on Wednesday and charged her with illegally showing a journalist secret reports about suspicious wire transfers by President Trump’s former campaign chairman Paul Manafort and others.

The Treasury official, Natalie Mayflower Sours Edwards, was arrested near Washington. She was charged with one count of unauthorized disclosure of the so-called suspicious activity reports, which banks use to flag potentially problematic transactions to the authorities, and one count of conspiracy to disclose the reports.

Her lawyer, Peter Greenspun, declined to comment.

The case is part of a crackdown by the Trump administration on leaks to journalists. On Monday, a former Senate Intelligence Committee aide pleaded guilty to lying to federal investigators about whether he had contact with reporters. But the aide, James A. Wolfe, denies that he distributed classified materials, and the Justice Department has not charged him with leaking information.

The case against Ms. Edwards is different. Disclosing suspicious activity reports to anyone who is unauthorized to see them is against the law, and the reports seldom — if ever — make their way into the public domain. When questioned by investigators, Ms. Edwards did not deny having shared them, court filings show.