Four executives of Google begin trial Tuesday in Milan on criminal charges of defamation and privacy violation in regard to a video posted on Google’s Italian site.

The case involves a three-minute cellphone video, posted in 2006 to Google Video, in which four youths in Turin tease a boy with Down syndrome. After an Italian advocacy group complained that the video was objectionable, Google quickly removed it from the site. Prosecutors argue that the video should not have been published at all.

The four executives charged were not involved directly in handling video from Italy. They include David Drummond, Google’s senior vice president and chief legal officer; George Reyes, its former chief financial officer; and Peter Fleischer, Google’s global privacy counsel, according to a Google spokesman. The fourth executive worked at Google Video in London, the spokesman said, declining to identify him.

It is rare for Internet company executives to face personal criminal charges and possibly jail time for the actions of their companies.

“To our knowledge, this is the first time an individual has been criminally charged for violation of data protection laws that occurred by the company he or she works for,” said Trevor Hughes, the executive director of the International Association of Privacy Professionals, which wrote about the case in its newsletter Monday. “This suggests that privacy is going to be more of a battleground.”

The case also raises again the question of whether Internet companies that allow users to submit content should screen items before they are published. This issue has mainly come up in the United States with regard to copyrighted music and video, and United States copyright law is meant to protect online services from liability if they respond to complaints quickly.

There are similar provisions in Europe, including Italian law. But there are questions about whether there are exceptions for young people and certain private information.

If the court holds that Google should have prevented the publication of the video simply because the subject didn’t authorize it, it could have very broad implications. In Europe, the subject of a photograph or video typically has the right to say how the image is used. But so far, charges haven’t been brought against user-generated content sites for hosting pictures posted without permission of the subjects.

In a statement, Google said the prosecution is misdirected: