The FBI reportedly failed to find any evidence supporting the charges.
There is a high legal bar for bringing federal civil rights charges, and federal investigators had for months signaled that they were unlikely to do so. The Justice Department plans to release a report explaining its decision, though it is not clear when.
Attorney General Eric H. Holder Jr., has said that he plans to have it done before leaving office, probably in the next month or two if his successor is confirmed.
Three law enforcement officials discussed the details of the federal investigation on condition of anonymity because the report was incomplete and Mr. Holder and his top civil rights prosecutor, Vanita Gupta, had not formally made a decision. Dena Iverson, a Justice Department spokeswoman, declined to comment.
The Justice Department is, for now, denying the reports. "This is an irresponsible report by The Washington Post that is based on idle speculation," spokesman Brian Fallon said.