The Justice Department has opened a criminal investigation into E. Jean Carroll, the 82-year-old former magazine writer who accused Donald J. Trump of sexual assault, according to two people with direct knowledge of the situation.

The investigation centers on whether Ms. Carroll committed perjury in civil lawsuits against Mr. Trump, according to the person, who spoke on the condition of anonymity to discuss an ongoing investigation. Ms. Carroll won a $5 million civil judgment against Mr. Trump that he had sexually abused and defamed her, which the president last November asked the Supreme Court to overturn. She also won a $83.3 million civil judgment against him in another defamation case.

An inquiry into Ms. Carroll would represent the latest chapter in Mr. Trump’s retribution campaign, which has been carried out by Justice Department officials. A number of figures who brought criminal and civil cases against Mr. Trump have come under the department’s scrutiny, including James B. Comey, New York Attorney General Letitia James and other adversaries of the president.....

Mr. Blanche has aggressively pursued investigations against people Mr. Trump has targeted. Last month, the department charged James B. Comey, the former F.B.I. director, over a social media post of seashells arranged in the numbers “86 47,” which prosecutors said was a threat against Mr. Trump. Mr. Comey has said he did not associate the phrase with violence and denied wrongdoing.

Mr. Trump’s revenge campaign kicked into high gear last September when he publicly demanded that the then-attorney general, Pam Bondi, move to prosecute several of his adversaries. Within several weeks, a newly selected prosecutor in the Eastern District of Virginia had indicted Mr. Comey and Ms. James. But both of those cases were thrown out by a judge, and, despite the newer indictment of Mr. Comey last month, the department has struggled to gain traction in a number of cases against Mr. Trump’s adversaries.....

The Justice Department’s leadership also has made extensive use of a provision that allows the designation of cases to handpicked prosecutors across the country, regardless of whether possible crimes occurred in their jurisdictions.

The department assigned its investigation into John Brennan, the former C.I.A. director, to the U.S. attorney in Miami, Jason Reding Quiñones, because he was seen as more willing to pursue a case viewed as questionable by other offices, according to former officials.