Emails from Apple Inc. (NASDAQ:AAPL) co-founder Steve Jobs may come back to haunt the company yet again. This month the company goes on trial in a class action lawsuit related to older generation iPods because they did not play music from competing stores, only music from iTunes and CDs.

Late Apple Inc. Co-Founder Steve Jobs "Testifies" In iTunes Case

Apple on trial again

This is the third major antitrust trial Apple has faced since Jobs’ death, and his emails are frequently used to argue cases back and forth. They were used as evidence in the previous two antitrust lawsuits as well. The New York Times reports that this time around, those emails offer important evidence, just as they did in those other two cases. Earlier this year, Jobs’ emails were used against Apple in an antitrust case involving e-book pricing.

In this case, Apple could have to pay about $350 million in damages, although that’s really chump change compared to the company’s last quarterly profit of $8.5 billion.

Jobs haunts Apple from beyond the grave

Lawyers generally tell companies executives to be careful when putting things in writing because their communications will often be used in court. However, Jobs’ emails have become a nightmare for lawyers attempting to defend the company because apparently he didn’t follow that bit of legal advice.

The former executive was known not only for his charm but also for his penchant for being a bully. His emails showcase both blunt threats of litigation against opponents and messages meant to charm the pants off potential business partners. Because of his emails, Jobs tends to be a plaintiff’s star witness against his own company.

Apple case starts tomorrow

The case involving iTunes is scheduled to begin tomorrow in Oakland, Calif. The class action lawsuit is being brought by consumers who allege that Apple was in violation of antitrust laws. The main issue in the case is that with the earlier generation of iPods, Apple forced consumers to keep using the iPod in order to be able to keep their music. If they wanted a new music player, they had to purchase Apple’s more expensive iPods rather than less expensive music players made by competitors.

Lawyers for the plaintiffs will argue that Jobs’ emails demonstrate that Apple was trying to keep competitors from entering the MP3 music player market in order to keep a stranglehold on the market. Judging from the content in some of the emails that have already been made public, it won’t be too difficult to make this argument.

For example, Jobs said in one email from 2003 that they needed to make sure that software company Musicmatch, which was opening up its own digital download music store, they couldn’t use an iPod.