Bobbi Kristina Brown
The relationship between Bobbi Kristina Brown and Nick Gordon has been described by friends as "tumultuous."Maury Phillips/Getty Images For A E Networks

Rumours have surfaced suggesting that Bobbi Kristina Brown may have been cheating on her boyfriend Nick Gordon.

According to Radar Online, a friend and neighbour of the couple, Debra Reis Brooks is quoted as saying that the 21-year-old may have been with another man before she was found unconscious in a bathtub at her Georgia home on January 31.

Bobbi Kristina, who was with Gordon and Maxwell Lomas before the accident, reportedly had an argument with her boyfriend the night before. Brooks said: "Nick and Max [Lomas] left and went out -- that's supposedly when this other guy came over to Krissi's. There was some discussion of some guy who came over and [he and Bobbi Kristina] fooled around — that's what Nick said."

Bobbi Kristina posted a selfie with Hall on social media just six hours before she was found unconscious.

Brooks claims Gordon was furious after he discovered that Bobbi Kristina had another man in her life. While Brooks did not name the man, Radar Online identified him as Gordon's friend, Duane Tyrone Hall. He was initially named in media reports as Edwin Demarco.

"If Nick caught Bobbi Kristina in bed with a guy, it would certainly make sense that a violent confrontation between him and Whitney's troubled daughter would have occurred," another source told Radar Online.

Police launched a criminal investigation into Bobbi Kristina's case after she was found to have unexplained bruises on her body. According to TMZ several sources reported a history of violence in the Brown-Gordon relationship with reports that police were called to the property a week earlier following a dispute. Friends said that the pair had a tumultuous relationship that allegedly revolved around drug use and Gordon was described as having a "short fuse".

During an intervention with TV doctor Dr Phil, Gordon admitted to battling drug addiction. The 25-year-old had appeared on the show after posting a series of worrying messages on Twitter that appeared to suggest he was suicidal. In an emotionally charged interview, Gordon broke down and threatened to kill himself.

The latest revelations of alleged cheating emerged days after Gordon released a statement through his lawyer begging for permission to meet his girlfriend who remains in a medically induced coma in a rehabilitation centre in Atlanta. He claims that since the incident the Brown family have refused to allow him to see Bobbi Kristina.

In a message released to People magazine through his lawyer Randy Kessler, Gordon, 25, says that he has been respectful of her family's wishes for him to stay away from the Atlanta medical facility, but now, as it appears she has suffered irreversible brain damage and hopes of her survival appear to be diminishing, he expressed a wish to see her.

Gordon had originally been welcomed into the family at the age of 12, by singer Whitney Houston who regarded him as a son. However, he and Bobbi Kristina shocked family and friends when they announced their engagement. It was rumoured that the pair had married, but Bobby Brown denied that a wedding had ever taken place.

As the family now consider bringing Bobbi Kristina back to her Roswell home, police are continuing to investigate the case which bears tragic similarities to the untimely death of Whitney Houston.