The judge in the Enron trial has ruled that jurors can find the energy firm’s former bosses guilty of deliberately avoiding knowledge of massive fraud.
The ruling has raised concerns among the defence team and legal experts.
Known as the “ostrich instruction”, because it refers to a person sticking their head in the sand, the ruling means that prosecutors will need a lower burden of proof to be successful.
However, Mr Skilling’s lawyers said that they were concerned by the judge’s decision.
“We have never asserted the ostrich defence,” said Mr Skilling’s lawyer, Daniel Petrocelli.
“We have said all along this was not a case of hear no evil, see no evil. It was a case of there was no evil.”
Legal experts said that another worry was that the prosecution has not followed a line of argument that would allow for this verdict.
Speaking to the New York Times, law professor Ellen Podgor said that instead of showing that Mr Lay and Mr Skilling shielded themselves from the truth, the prosecution has claimed they deliberately chose to mislead investors and staff.
“They have presented a case where this guy was on a soap box telling public lies,” she explained.
Lawyers for Mr Lay and Mr Skilling rested their defence on Monday and jury deliberations are due to start next week. The trial has been running for 15 weeks.
During questioning that has often been emotional and combative, Mr Lay has portrayed himself as a trusting man who was let down by corrupt staff, especially former finance chief and prosecution witness Andrew Fastow.