A Justice Department investigation into influence-peddling on Capitol Hill is focusing on a "first tier" of lawmakers and staffers, both Republicans and Democrats, say sources close to the probe that has netted guilty pleas from lobbyist Jack Abramoff.

 Law-enforcement authorities and others said the investigation's opening phase is scrutinizing Sens. Conrad Burns, Montana Republican; Byron L. Dorgan, North Dakota Democrat; and Minority Leader Harry Reid, Nevada Democrat, along with Reps. J.D. Hayworth, Arizona Republican, and Bob Ney, Ohio Republican.

 A source working with the Justice Department on the investigation told The Washington Times that Abramoff was questioned during several interviews about the lawmakers and their purported ties to the lobbyist and his former clients.  

 The source said prosecutors asked Abramoff whether the lawmakers had performed "official acts" in exchange for campaign cash or other favors. Although it is unknown whether any of the five will be charged in the case, the source said Abramoff was being "prepped" by five Justice Department attorneys in that event.