Bobbi Kristina - Nick Gordon Says Drugs Did Her In ... Not Him

Bobbi Kristina's boyfriend Nick Gordon has not said a word about the bathtub incident that apparently will prove fatal, but TMZ now knows Nick's story ... that he did nothing to harm Bobbi Kristina and drugs did her in.

A member of Bobby Brown's family recorded Nick on February 21, 3 weeks after Bobbi Kristina was rushed to the hospital. Even though Nick didn't know he was being taped, the call was legally recorded because Georgia is a 1-party state.

Nick says, "I'll tell you the honest truth, Krissy, she was under a lot of stress and we were all doing drugs and you know, all, all drinking, bro."

And then he said this: "She just did too much man. She, listen, listen bro. I will officially stay from bath tubs forever, I'll tell you that."

He then rails on those who think Bobbi Kristina's injuries prove he tried to kill her, saying, "When Krissy wakes up she'll tell the truth to everybody. Everybody will feel stupid as f***... You know Krissy got in an accident 2 days before this happened and the man is in critical condition right now."

He then warns the family, saying, "If they take her off that life support, the police are going to have to take me down bro."