Jack Abramoff, once the most powerful lobbyist in Washington, is now at the center of a case that involves tens of millions of dollars and more than a dozen key members of Congress.
Abramoff pleaded guilty to three counts of conspiracy, honest-services mail fraud and tax evasion. Officials said he had brought corruption to a new level at the Capitol.
"The corruption scheme with Mr. Abramoff was very extensive, and the investigation continues," said Alice Fisher, the head of the Department of Justice's criminal division.
One aspect of Abramoff's corruption scheme was the free trips he provided to politicians to the Super Bowl, a golf resort in Scotland and the northern Mariana Islands in the South Pacific.
An ABC News hidden camera recorded Rep. Tom DeLay, R-Texas, as he arrived in the northern Marianas and was greeted and hugged by Abramoff.
Delay was only one congressman out of dozens who accepted the lobbyist's trips and campaign contributions.
"There are many members of Congress who will not sleep well tonight," said Fred Wertheimer, president of Democracy 21, a nonprofit, nonpartisan organization that monitors government decisions to ensure their fairness. "This is a blockbuster of an investigation that will reach deep inside the power structure.
Federal authorities told ABC News that Abramoff started to provide details of his dealings with DeLay, and to pinpoint a long list of senators and congressmen more than a year ago.
At least nine have since returned campaign contributions from Abramoff, and all, including DeLay, have denied any wrongdoing.
Officials told ABC News that the first congressman to be indicted for bribery is expected to be Rep. Bob Ney, R-Ohio.
He is the official described in court papers today as "Representative No. 1," a person who took trips, gifts and items of value to "support and pass legislation" and place statements in the Congressional Record.
Officials also say that at least two former members of the Bush administration's Interior Department have also been tagged by Abramoff. He has produced hundreds of e-mails, in which details of the quid pro quo of the bribes are allegedly laid out.
ABC News' Maddy Sauer, Rhonda Schwartz, Vic Walter, and Avni Patel contributed to this report.