What could a corrupt energy company, a 'milkshake murderer' and a paedophile possibly have in common?
Each underestimated the power of digital evidence and the ability of computer forensics experts to follow its trail.
Digital or computer forensics - the application of science and engineering to the recovery of evidence - has taken an increasingly important role in solving crime. Experts are able to extract deleted, encrypted or damaged file information from electronic devices, including personal computers and mobile phones.
United States-based energy company Enron, which employed about 22,000 people and claimed revenues of almost US$101 billion in 2000, filed for bankruptcy in late 2001, when it was revealed the firm had systematically committed accounting fraud. It was the largest corporate failure in the US at the time.
When prosecutors began to investigate the digital records of Enron, its accounting firm, Arthur Andersen, and key executives, they found the damning evidence they needed. The FBI's five-year investigation yielded more than 31 terabytes of data, gathered from more than 130 computers, thousands of e-mails and 10 million pages of documents. A terabyte is equivalent to 1,000 gigabytes; at an average of 5,000 characters per page, 1TB of disk space can hold about 250 million pages of text (a stack of paper 10 miles high if printed on both sides).
Andrew Rosen, the president of computer forensics software and services firm ASR Data, which undertook the Enron data recovery, says cases involving such vast amounts of data are increasing, especially since personal computers with a 1TB hard-disk are no longer rare.