Former Enron finance chief Andrew Fastow has pleaded guilty to fraud charges stemming from his role in the collapse of the scandal-hit firm.
Will Mr Fastow's gulity plea lead to more prosecutions?
The plea forms part of a deal with prosecutors which could lead to charges being brought against the US energy giant's most senior executives.
Mr Fastow has agreed to pay fines of about $23m (£13m), and could also face up to 10 years in prison.
He is the most high-profile figure to plead guilty since Enron collapsed.
Enron, a previously highly respected energy trading firm, went bust in December 2001 after it emerged that the company had concealed millions of dollars in debts.
As chief financial officer during Enron's rise, Andrew Fastow was mastermind of the complex finances that masked the true state of the company's accounts.
Revelation of the accounts blackhole rocked investor confidence in blue-chip US firms.
It also wiped out the savings of thousands of Enron employees who had been encouraged to invest in the firm's shares.
Mr Fastow's wife, Lea, who also worked for Enron, separately pleaded guilty to a tax fraud charge.
She could face five months in prison, as well as a $250,000 fine.
It is reported that the couple, who have young children, agreed to strike a deal with prosecutors in return for shorter prison sentences, and in order to avoid both being jailed at the same time.
Under normal circumstances, Mr Fastow would have been sentenced to up to 20 years in prison if found guilty.
The former Enron chief financial officer is expected to help prosecutors as they put together a case against his former colleagues.
Their most likely targets are Enron's former chief executive, Jeff Skilling, and its former chairman, Kenneth Lay.
Both have persistently denied any wrongdoing, and no charges have been brought against either of them so far.
Mr Fastow is to be sentenced on 19 April.