An investigation into whether Bobbi Kristina Brown was gambling in Las Vegas last month has been closed.

The 19 year old - whose parents are late singer Whitney Houston and her former husband Bobby Brown - was caught on video enjoying slot machines when she was in the city in May to accept an honour for her late mom at the 2012 Billboard Music Awards.

The legal gambling age in the state of Nevada is 21 but the teen was spotted inside the casino with her 22-year-old boyfriend and adopted brother, Nick Gordon.

However, gaming board deputy chief David Salas told E! News that, upon completion of their investigation, there was not enough evidence to support criminal charges.

Although the youngster was recently forced to deny rumours she has been abusing illegal DRUGS, her father has insisted she won't make the same mistakes he and her mother - who have both battled substance abuse problems - did.

He said recently: ''Any parent that has a teenager in their life, they go through things. They go through phases that they might not be doing exactly what you want them to do in life, but they grow out of it, and my baby girl has grown out of it. I trust and believe that she's smart enough to not go down the same road that maybe I did in the past or her mother did in the past. She's extremely smart.''