A 2002 e-mail suggests that an investigation commissioned by The SCO Group failed to produce any evidence that Linux contained copyrighted Unix code.

The e-mail, which was sent to SCO Group CEO Darl McBride by a senior vice president at the company, forwards on an e-mail from a SCO engineer. In the October 13, 2002, e-mail, engineer Michael Davidson said "At the end, we had found absolutely nothing ie no evidence of any copyright infringement whatsoever."

The e-mail was posted on Thursday to Internet law site Groklaw.

SCO sued IBM in 2003 for more than US$1 billion, alleging that IBM had misappropriated Unix technology to which SCO claimed intellectual property rights.

A SCO representative said that the e-mail was authentic, but noted that the e-mail doesn't say when the SCO investigation took place or what tools were used.

"That e-mail probably creates a lot more questions than it answers," SCO spokesman Blake Stowell said. "We'll be fully prepared to address that, but we will be doing that in a court setting if it is necessary."

An IBM representative declined to comment.

In the e-mail, Davidson shares his findings with Senior Vice President Reg Broughton, who then forwards that note to McBride.

"The project was a result of SCO's executive management refusing to believe that it was possible for Linux and much of the GNU software to have come into existence without someone somewhere having copied pieces of proprietary UNIX source code," Davidson said in the e-mail. "The hope was that we would find a 'smoking gun' somwhere (sic) in code that was being used by Red Hat and/or the other Linux companies that would give us some leverage."

Although the details of the investigation are not spelled out in the e-mail, Davidson does note that it was done by Bob Swartz, a consultant hired by SCO.

"An outside consultant was brought in because I had already voiced the opinion (based on very detailed knowledge of our own source code and reasonably broad exposure to Linux and other open source projects) that it was a waste of time and we were not going to find anything," he wrote in the e-mail.

Davidson goes on to note that Swartz spent four to six months looking at the Linux kernel as well as a large number of libraries and utilities, comparing them to several different versions of AT&T's Unix source code.

Stowell said that IBM has brought up the e-mail in court and noted that a judge has refused to dismiss SCO's suit.

"It doesn't really spell out anything," Stowell said of Davidson's e-mail.

In February, US District Judge Dale Kimball denied a partial summary judgment request filed by IBM. However, in his ruling he severely criticised SCO for producing almost no evidence to date to support its claims.

"Despite the vast disparity between SCO's public accusations and its actual evidence -- or complete lack thereof -- and the resulting temptation to grant IBM's motion, the court has determined that it would be premature to grant summary judgment," Kimball wrote. "Viewed against the backdrop of SCO's plethora of public statements concerning IBM's and others' infringement of SCO's purported copyrights to the Unix software, it is astonishing that SCO has not offered any competent evidence to create a disputed fact regarding whether IBM has infringed SCO's alleged copyrights through IBM's Linux activities."

The case is scheduled to go to trial in early 2007.

CNET News.com's Michael Kanellos contributed to this report.