From the New York Times:

… The whistle-blower, a C.I.A. officer detailed to the White House at one point, first expressed his concerns anonymously to the agency’s top lawyer. …

Dean Baquet, the executive editor of The New York Times, said The Times was right to publish information about the whistle-blower. “The president and some of his supporters have attacked the credibility of the whistle-blower, who has presented information that has touched off a landmark impeachment proceeding,’’ Mr. Baquet said. “The president himself has called the whistle-blower’s account a ‘political hack job.’’’

Mr. Baquet added, “We decided to publish limited information about the whistle-blower — including the fact that he works for a nonpolitical agency and that his complaint is based on an intimate knowledge and understanding of the White House — because we wanted to provide information to readers that allows them to make their own judgments about whether or not he is credible. We also understand that the White House already knew he was a C.I.A. officer.”