The My Prerogative singer was interviewed for a 20/20 news special, which will air in America on Tuesday (07Jun16), alleging that Nick "knows what happened" and what led to the deaths of his former wife in 2012 and daughter in July 2015.
Gordon is currently battling a $10 million (£7 million) wrongful death lawsuit filed against him by Bedelia Hargrove, the conservator of Bobbi Kristina's estate.
Fighting back tears in the TV chat with ABC's Robin Roberts, Brown says: "The same thing that happened to my daughter is what happened to Whitney. There was only one person who was around on both occasions... I won't say his name... He knows what happened. I don't know what happened that night, but he does."
Now Gordon has responded in a statement released by his attorney, Jose Baez.
"We have repeatedly said that Nick Gordon is innocent of any wrongdoing," the statement, released to People, read. "He has not been charged with any crime. Enough is enough; let's end this baseless speculation."
Bobbi Kristina was found unresponsive and face down in a bathtub at the Georgia home she shared with Gordon on 31 January, 2015. Gordon's attempts to resuscitate the 21-year-old failed, and she was rushed to hospital where she was placed in a medically-induced coma. She never regained consciousness and died in July (15).
The drowning incident was eerily similar to her mother's death - Whitney was found dead in a bathtub in her suite at the Beverly Hilton Hotel in 2012 and her death was ruled an accidental drowning with cocaine found in her system.
Despite Brown's comments about Bobbi Kristina's death, Gordon previously alleged that his late girlfriend had a troubled relationship with her father.
"He (Bobby) hurt his own daughter, not me," Gordon said during an appearance on America's Dr. Phil show. "I was the one there for her while she was dealing with him not being there. He's not a reasonable person so I'm not planning on talking to him and I really don't want to."
Last month (May16), Brown joined Hargrove as a plaintiff in the civil case against Gordon.
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