'Idol' Contestant Michael Johns -- Best Friend Claims Cover-Up ... Alcohol Killed Him

The wife of "American Idol" contestant Michael Johns created a lie to cover-up the real cause of death ... alcohol abuse ... this according to his best friend.

Stacey Vuduris filed legal docs -- obtained by TMZ -- claiming Torrey Gambill has been on a hate campaign, blaming her for Michael's death in August and sending her abusing texts.

But Torrey has fired off legal docs of his own, claiming Stacey concocted a lie after he found Michael dead in his Orange County apartment.

After Michael died, we reported Stacey's story -- that Michael had an ankle injury that led to a fatal blood clot. But law enforcement told us at the time Michael had engaged in heavy alcohol use prior to death.

Torrey quotes from a text Stacey sent him shortly after Michael died, saying, "I'd rather it be said he died at home if that's ok with u .. he would want that."

Stacey continued, "I rather that then 'alcoholic' stuff ... his good friends would never say anything ... so I don't think that will come out. At least blood clot sounds sudden."

Torrey also says Michael and Stacey were separated, and that Michael "insinuated" she had a boyfriend. He says Stacey put Michael through hell his last year.

According to legal docs ... Stacey and Torrey settled their beef without a judge's order.