The day after President Trump asked James B. Comey, the F.B.I. director, to end an investigation into his former national security adviser, Mr. Comey confronted Attorney General Jeff Sessions and said he did not want to be left alone again with the president, according to current and former law enforcement officials.
Mr. Comey believed Mr. Sessions should protect the F.B.I. from White House influence, the officials said, and pulled him aside after a meeting in February to tell him that private interactions between the F.B.I. director and the president were inappropriate. But Mr. Sessions could not guarantee that the president would not try to talk to Mr. Comey alone again, the officials said.