Who is Jack Abramoff?

He is a former weightlifting champion, conservative activist and film producer from Los Angeles who was one of Washington's most powerful lobbyists of the last decade.

When the Republican Party regained control of Congress in 1994, Abramoff, a former chairman of the student wing of the Republican Party, abandoned Hollywood to work on Capitol Hill as a lawyer and lobbyist.

Friends from his student days, including Ralph Reed, the founder of the Christian Coalition, a conservative activist group, introduced Abramoff to the top tier of congressmen in Washington, allowing him to grow a lobbying practice that charged clients $750 an hour.

Between 2000 and 2005, official records show that Abramoff, 46, directed $4.4 million in contributions to more than 20 congressmen, both Democrats and Republicans, on behalf of his clients.

What did he do wrong?

After a lengthy investigation by the Justice Department, Abramoff pleaded guilty yesterday to tax evasion, mail fraud and bribing public officials "in exchange for official acts".

Abramoff also admitted to persuading a congressional aide to lobby his former employer within a year of leaving his job, a violation of Congress rules. As part of his guilty plea, Abramoff has agreed to tell prosecutors how he used lobbying fees to lavish expensive meals and holidays on congressmen and their staff in return for their help in passing and blocking legislation.

Abramoff's crimes centred on more than $82 million in fees paid to him and his business partner, Michael Scanlon, by American Indian casino operators, who employed him to help secure favourable legislation for their tribes.

Without telling the tribes that he and Scanlon were partners, Abramoff suggested that they use Scanlon's lobbying firm, Capital Campaign Strategies, and a public relations firm called Grassroots Interactive, also run by Scanlon.

Scanlon and Abramoff then split the profits from the firms. Abramoff netted more than $26.7 million in kickbacks from the deals. Scanlon received $19.7 million. Scanlon, a former senior aide to Tom DeLay, the former House Republican leader under investigation for corruption in a separate case, pleaded guilty to the fraud in November.

Among other things, Abramoff used the fees to buy Signatures, a restaurant in Washington popular among Republican politicians and to take congressmen on all expenses trips to play golf at St Andrews in Scotland. In return, he asked them to lift federal bans on gambling in certain states and to modify legislation relating to internet gambling.

Who is named in the investigation?

Abramoff's plea agreement referred to only one unnamed congressman, acknowledged by his lawyer to be Bob Ney, a Republican from Ohio. The plea says that Mr Ney agreed to introduce legislation in support of a Texas tribe, the Tigua Indians, to help them re-open a closed casino.

Mr Ney also supported a $147 million deal made by a casino company owned by Abramoff by praising them in the official Congressional Record. The plea says that Mr Ney, who denies all wrongdoing, also agreed to meet clients of Abramoff in Russia to help them obtain a visa to visit America. The plea also refers to two anonymous congressional staffers, one of whom is reported to be Tony Rudy, the former deputy chief of staff to Mr DeLay.

Prosecutors said yesterday that Abramoff was co-operating in an "ongoing criminal investigation" and is expected to describe deals with as many as six members of Congress, who will be named only if they are charged with a crime. "The corruption scheme with Mr Abramoff is very extensive," said Alice Fisher, head of the Justice Department's criminal division. "We're going to follow this wherever it goes."

Why is the case so damaging?

Abramoff was one of the principal dealmakers on Capitol Hill with longstanding friendships and alliances that went to the heart of America's conservative establishment. His case has already led to the arrest of David Safavian, a White House procurement official who is accused of obstructing the investigation.

Although it is unclear whom Abramoff will name in his co-operation with prosecutors, questions are already being asked of Mr DeLay, who once described Abramoff as one of his "closest and dearest friends".

Last night, congressmen were queuing up to return political donations that could be sourced to Abramoff and his clients. The House Speaker Dennis Hastert, an Illinois Republican, said he would give $57,250 received from Abramoff to charity.

Senator Conrad Burns of Montana, a Republican who received the most donations from Abramoff said he would give away his donations last month. Senator Byron Dorgan, a Democrat from North Dakota said he would send Abramoff-related donations back to the tribes.

Times Recommends

• No apology for Germany’s own Nazi victims
• Intricate web of fear and hope tying down deal
• Victims remembered a year after Mumbai attacks