WASHINGTON -- Rep. Bob Ney, R-Ohio, has agreed to plead guilty to federal criminal charges related to his dealings with the corrupt lobbyist Jack Abramoff, lawyers and others with knowledge of the investigation said Thursday. A guilty plea would make Ney, a six-term congressman, the first member of Congress to confess to criminal charges in the Abramoff investigation, which has focused on the actions of several current and former Republican lawmakers who had been close to the former lobbyist. People with detailed knowledge of the investigation said Ney had entered an in-patient facility in recent days for treatment of alcoholism, making it uncertain whether he would appear at a court hearing to announce the plea. Lawyers and others would speak only anonymously because of concern they would anger prosecutors.