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