FBI agents have arrived at Enron's headquarters in Houston to investigate allegations of document shredding.
An Enron attorney said company officials seized a rubbish bin filled with shredded documents after learning of the allegations. The company says the FBI was called in at its request.
Meanwhile shareholders suing the fallen energy giant have asked a federal judge to bar the company and its former auditor from destroying any more records.
Enron said it has posted security guards to block employees from floors holding accounting and finance records.
"The company has done everything you'd expect under these circumstances," Enron attorney Mr Kenneth Marks told US District Judge Melinda Harmon.
The judge urged attorneys for both sides to come up with a plan to protect company documents and get back to her on Wednesday.
Enron's former auditor, Arthur Andersen, acknowledged this month its Houston office had shredded Enron-related documents. The office is already under a court order not to destroy any more of the firm's files.
In Washington, congressional investigators said they will subpoena senior officials of Arthur Andersen, including the chief executive, to force their testimony in the controversy.
Mr Ken Johnson, spokesman for the House Energy and Commerce Committee, said subpoenas are going to Andersen chief executive Mr Joseph Berardino, sacked auditor David Duncan, lawyer Ms Nancy Temple and risk manager Mr Michael Odom.
Enron slid into the biggest bankruptcy in US history last month after investigators began looking at a series of complex partnerships that were used to keep hundreds of millions in losses off the books.
Shareholders are suing Enron executives and directors over more than $1 billion they gained from selling stock from 1998 through last November.
PA