I am a firm believer that if you are going to take the pay and perks of being the "top guy", you also take the responsibility for what the people below you do. If Lay and Skilling knew that Fastow was doing something inappropriate, they should have taken action. Worse, if they did not know what he was doing, they should have and, therefore, are equally liable.
Lay was convicted on all six counts against him of conspiracy to commit securities and wire fraud. Skilling was convicted on 18 similar counts and one count of insider trading. He was acquitted on the remaining nine.