The Paper Trail Enron Corp and its accounting firm Arthur Andersen are under intense scrutiny from Congress and federal law enforcement agencies for their roles in the failure of the world's largest energy-trading concern.

February 2001 Executives at Arthur Andersen - the accounting firm of bankrupt Enron Corp. - may be aware of potential problems at the energy giant much earlier than previously acknowledged, an internal memo indicates. The e-mail, whose existence was confirmed in January 2002 by a staffer on the House Energy and Commerce Committee, suggests senior managers at Andersen are raising concerns about Enron's accounting practices and considering dropping Enron as a client.

August 2001 Andersen officials are warned by an Enron vice president, Sherron Watkins, of her serious concerns about the off-the-books deals at Enron and that the company "will implode in a wave of accounting scandals," another document, which was obtained by congressional investigators and released in January 2002, indicates.

Oct. 23, 2001 Under the direction of chief auditor for Andersen's Enron account, David Duncan, the accounting company begins a two-week document destruction effort of Enron related paperwork shortly after learning the Securities and Exchange Commission was asking Enron for accounting information. Duncan later tells congressional investigators the destruction of documents was ordered from higher up.

Nov. 8, 2001 As part of its investigation into Enron, the SEC subpoenas Andersen for Enron documents.

Nov. 9, 2001 The destruction of Enron documents ends when Duncan's assistant e-mails secretaries to "stop the shredding."

Dec. 2, 2001 Enron files for Chapter 11 bankruptcy.

Dec. 12, 2001 Congressional hearings begin on the collapse of Enron.

Dec. 13, 2001 Executives from Andersen tell Congress they warned Enron about "possible illegal acts" after the company failed to provide crucial data about its finances to Andersen.

Jan. 10, 2002 Andersen admits its employees disposed of or deleted a number of documents relating to Enron's audit.

Jan. 15, 2002 Andersen fires Duncan, saying he had directed a hurried destruction of documents in October after learning that federal regulators were beginning to look at Enron's books. Four other partners in its Houston office are stripped of management responsibilities.

Jan. 16, 2002 Duncan tells House Energy and Commerce Committee investigators that the accounting firm's lawyers suddenly began emphasizing the firm's policy allowing destruction of some documents. He also says an Oct. 12 memo from one of Andersen's lawyers was the beginning of an effort to discard many records.

Jan. 17, 2002 Enron abruptly fires its accounting firm, Arthur Andersen, in the aftermath of the auditor's massive destruction of documents.

Jan. 18, 2002 Andersen takes out a full-page ad in national newspapers that lists steps the firm has taken to correct problems concerning its handling of the Enron account.

March 7, 2002 A federal grand jury indicts Andersen for obstruction of justice in the Enron scandal, the first criminal charges in the nation's biggest bankruptcy. The one-count indictment comes after Andersen spurned a 9 a.m. deadline to plead guilty to charges stemming from its admitted destruction of Enron-related documents. The indictment is unsealed a week later.

March 20, 2002 Andersen's lawyers plead innocent to the obstruction-of-justice charge and call the first indictment "senseless." The same day, Anderson launches a publicity campaign to prevent business from disintegrating. Taking out full-page advertisements in leading newspapers, headlined "Why We're Fighting Back," the company calls the government's action "a tragically wrong indictment of our whole firm."

March 26, 2002 Andersen chief executive Joseph Berardino resigns, bowing to mounting pressure. His announcement comes four days after former Federal Reserve chairman Paul Volcker urges top management to step aside so he can install and head an independent board in a last-ditch plan to save the company.

April 8, 2002 Taking a "painful" but inevitable step after suffering critical damage from its role in the Enron scandal, Andersen says it will lay off 7,000 employees as the 89-year-old accounting giant fights for its survival. The dismissals will pare its U.S. work force of 26,000 by more than a quarter.

April 9, 2002 Duncan pleads guilty to criminal obstruction by persuading coworkers and others to shred documents to thwart the government's investigation into the collapse of Enron. Duncan also agrees to cooperate with prosecutors pursuing obstruction charges against Andersen and in the broader investigation of the collapse of Enron. Read the obstruction of justice charges or the notice of related cases.

May 6, 2002 Jury selection begins in Houston federal court in the first criminal case to emerge from the Enron collapse. Attorneys face distinct challenges as they tackle the case that threatens to provide the knockout punch to the embattled accounting firm.

May 9, 2002 Andersen announces that rival Deloitte & Touche would hire away about 2,000 Andersen workers, including nearly 200 partners, across the U.S. Andersen did not disclose terms of the agreement. Earlier, KPMG Consulting Inc. announced plans to acquire as many as 23 business consulting units of Andersen Worldwide's member firms for up to $284 million. Ernst & Young LLP acquired Andersen's Pittsburgh audit and tax practices in a deal involving 87 Andersen employees.

June 14, 2002 A jury convicts Arthur Andersen of obstruction of justice in the investigation into the sudden collapse of Enron. The conviction could put Andersen, which has already lost more than a third of its public clients, out of business.

Oct. 16, 2002 The maximum sentence allowed by law, five years of probation and a $500,000 fine, is handed down to the former accounting giant for its role in the Enron scandal. There were no individual defendants in the trial. The firm and many of its former partners still face lawsuits from shareholders left with near-worthless stock after failures of Enron and WorldCom Inc.

April 25, 2005 Arthur Andersen reaches an undisclosed settlement with WorldCom investors who claimed the outside auditor failed to protect them from WorldCom's historic $11 billion accounting fraud. The plaintiffs said financial statements for 1999, 2000 and 2001 contained false statements and that Arthur Andersen issued its audit opinions with an "intent to deceive, manipulate or defraud." Andersen insisted that each of its audit opinions was generated in good faith.

May 31, 2005 The Supreme Court unanimously overturns Arthur Andersen's conviction for destroying Enron Corp.-related documents before the company's collapse. The decision says jury instructions at the trial - which virtually destroyed Andersen - were too vague and broad.