The ENQUIRER has discovered  the nanny John Travolta hired to care for his disabled son Jett went through a Scientology drug program before the teen's tragic death.

Jeff Kathrein, 29, took a course called a "Drug Rundown" that the controversial church's Web site says "addresses the devastating mental and spiritual damage that can follow in the wake of drug use."

If a Scientologist enrolls in a Drug Rundown, "it could indicate that his case supervisor believed he needed to get drugs out of his system," Jeff Jacobsen, a Scientology expert, told The ENQUIRER.

Jett, 16 was found unconscious in a bathroom of the family's Bahamian vacation home on Jan. 2. An autopsy determined the teen died from a seizure. The youngster suffered from frequent seizures and needed to be closely monitored, said his family.

Kathrein occupied an adjoining room when the tragedy happened. A baby monitor linked the rooms, and a bell was set to sound when Jett entered the bathroom.

A Scientology publication, tracked down by The ENQUIRER, confirms the nanny's involvement in the treatment program, which the Scientology Web site touts as helping people escape "the harmful effects of drugs, medicine or alcohol."

Scientology watchdog Kristi Wachter, who runs a Web site called Truthaboutscientology.com, told The ENQUIRER that the magazine is published by the Church of Scientology Celebrity Centre in Hollywood, "It's likely that Jeff completed the Drug Rundown sometime in early 2008."

A Travolta rep told The ENQUIRER that if Kathrein had been in the substance abuse program, it was of "no significance" to the tragedy.

Scientology spokesman Tommy Davis added that while Kathrein may have completed the drug and alcohol program, it "doesn't mean he was an addict."

FOR the full story pick up the latest ENQUIRER!