Enron Corp.’s outside law firm conducted a cursory probe in the fall of 2001 of accounting complaints raised by former finance executive Sherron Watkins that asked executives and accountants who had already approved financial structures if they were proper, a lawyer with the firm testified Wednesday.

And Max Hendrick III, a partner with the Houston law firm Vinson & Elkins who helped conduct the investigation, testified during the criminal fraud and conspiracy trial of Enron founder Kenneth Lay and former chief executive Jeffrey Skilling that the firm would have had to bow out if a more extensive probe were required because of its relationship with Enron.