Another lawyer, Robert S. Bennett, who represents Enron, previously disclosed that Mr. Lay used some stock to repay a loan late last year.
Some critics have called on Mr. Thompson to step down from the case as well because his former law firm represented both Enron and Arthur Andersen.
Robert S. Bennett, a lawyer representing Enron, said that the company was investigating the reports of shredded documents.
Mr. Fastow was negotiating deals on behalf of the partnerships across the table from his own subordinates, who were representing Enron.
Six other Washington tax lawyers, some of whom represent Enron or its creditors, agreed.
Mr. Susman sounds disappointed to have been caught on the wrong side of the fence, representing Enron rather than performing in his more common role as a plaintiff's lawyer.
"Were it not for the fact that I was representing Enron in October, I would probably be suing them," Mr. Susman said.
The agent also talked to lawyers representing Enron.
Lawyers representing Enron and the company's former directors have disputed the findings.
But attorney Robert Bennett, who is representing Enron, said the report was "grossly unfair" and that it leapt to "unfounded conclusions".