Bobbi Kristina Brown
Bobbi Kristina Brown (L) and Nick Gordon attend the opening night of "The Houstons: On Our Own" in New York October 22, 2012.Reuters

The late Bobbi Kristina Brown's estate has amended a lawsuit filed against her boyfriend Nick Gordon alleging that he gave her a toxic cocktail following an explosive fight.

The amended lawsuit also claims that Gordon was the one who placed Bobbi Kristina facedown in the bathtub that she was found lying unconscious and unresponsive.

Bobbi Kristina, the only child of the late Whitney Houston, died on 26 July, about six months after the 31 January tragedy.

The amended lawsuit was filed on 7 August and it claims that early on 31 January Gordon returned to the home he shared with Bobbi Kristina after "being all night on a cocaine and drinking binge," and the duo soon began arguing.

Gordon is believed to have accused Bobbi Kristina of cheating on him in a fight that lasted for about half an hour. "Everything abruptly became quiet" and Gordon "gave Bobbi Kristina a toxic cocktail rendering her unconscious and then put her face down into a tub of cold water causing her to suffer brain damage," the lawsuit claims, according to Radar Online.

However, a close family friend told the publication that there wasn't any hint of the tragedy as he hadn't witnessed and flare ups between Bobbi Kristina and Gordon.

 "I didn't sense anything bad," noted Sammy Tawil. "She wasn't depressed. I haven't personally seen any flare-ups, fighting or physical contact with her or Nick."

Recounting a telephone conversation he had with Bobbi Kristina before she was found unconscious, Tawil said the 22-year-old, who was like a daughter to him, sounded upbeat.

"I spoke with her the day before she was found," Tawil said. "She wasn't crying, she was upbeat, excited to go to L.A. She wanted to go in the studio."

However, he added that Bobbi Kristina missed her mother even though it had been three years since Whitney passed away. "She was still grieving for three years and never got over her mom's death. She was definitely missing her mom."

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