Bobbi Kristina Brown's Life and Accident Examined in New Book

Ian Halperin writes about Brown's life and troubles.

“It’s terrible what happened to this girl who was entering the prime of her life and had so much to offer,” author Ian Halperin said of Brown, 22.

“There were allegations of drugs and alcohol,” Halperin said. “She never dealt properly with the loss of her mother.”

Though Brown’s childhood was turbulent, Halperin said, she and Houston were extremely close and Houston’s death sent her daughter into a downward spiral.

The downward spiral led Brown to surround herself with enablers who were just using her for her access to Houston’s money, Halperin said. Those friends included Nick Gordon, who was at the home when Brown was found face-down in the bathtub.

In one of the book’s most explosive claims, Halperin said he is not convinced what happened in January was an accident at all and added that he believes there is evidence suggesting foul play.

“There’s no doubt the circumstances are highly suspicious because she was found in a bathtub of cold water,” Halperin said. “There is a criminal investigation going on as we speak.”

Police in Roswell, Georgia, confirmed a criminal investigation is ongoing, though no decision has yet been made to prosecute anyone.

“He’s been at her bedside almost 24/7 since the accident happened,” Halperin said. “And he’s believing a medical miracle is possible.”

Nick Gordon and Bobby Brown did not respond to ABC News' attempts to reach them for comment.