By Silvia Molteni

MILAN (Reuters) - Italian prosecutors are preparing to file charges against four current or former Google Inc <GOOG.O> executives over a 2006 video on the Internet provider's Italian-language site, court sources said on Friday.

The video shows a teenager with Down syndrome taunted by other youths.

Prosecutors have concluded an inquiry that could lead to the executives being charged with defamation and failure to exercise control over personal data, said the sources, who spoke on condition of anonymity.

Under Italian law, the conclusion of an inquiry is usually preparatory before the case goes to a judge to decide whether charges should be filed. The story was first reported by the Wall Street Journal on Friday.

The former and current Google executives include the top legal representative and chairman of Google's Italian unit at the time, a now-retired Google Italy board member, an executive responsible for Google's privacy policies in Europe, and the then-head of Google Video for Europe.

An Italian advocacy group for people with Down syndrome, Vividown, and the boy's father lodged a complaint over the video in November 2006.

The video was filmed from a mobile phone in late May or early June 2006. It shows four male high school students in the Italian city of Turin humiliating the youth with Down syndrome.

The four teens face charges in Turin over the case. Charges could be dropped if they show a judge they have straightened themselves out, Vividown attorney Guido Camera told Reuters.

A Google spokesman said the company would continue to cooperate with Milan prosecutors "to show that all Googlers under investigation have no involvement in the Vividown case."

(Additional reporting by Ajay Kamalakaran in Bangalore, India; editing by Jeffrey Benkoe)