Enron's former CEO Jeffrey Skilling is appealing his conviction for the role he played in the collapse of the former US energy giant.

Skilling's attorney, Daniel Petrocelli, filed a motion in the US Court of Appeals on Friday, almost a year after his client was ordered to serve more than 24 years in prison.

In May last year, Skilling and Enron chairman Kenneth Lay were convicted of fraud. However, Lay died a month later of a heart attack, removing his conviction and indictment from the record.

Skilling's 200-page appeal now questions court proceedings of May last year, which led a jury to convict Skilling of 19 counts of fraud as well as insider trading and conspiracy.

Petrocelli also took the opportunity to criticise the way in which district judge Sim Lake presided over the case, the sentence length and the actions of prosecutors. He said that weaknesses in the case prompted the government to 'resort to novel and incorrect legal theories, demand truncated and unfair trial procedures, and use coercive and abusive tactics.'

The court papers further try to defer any blame on Skilling's part to that of the former CFO, Andrew Fastow, CFO.com reports.

Petrocelli attacked prosecutors who interpreted Skilling's failure to ensure the accuracy of financial statements as an indication that he had stolen from the company. He argued that it was Fastow who admitted to stealing money from Enron and that Skilling had not.

Skilling is serving his time in a federal prison in Waseca, Minnesota, while Fastow – who took a plea deal – is serving a six-year sentence in Louisiana.

Further reading:

The Enron, the aftermath, five years on

Enron ex-CEO Skilling appeals conviction

Heads Up: Jeffrey Skilling wants a new trial