Having carried out a post-mortem on the what could have been responsible for the death of Bobby Houston, officials say the cause of her death has been known but will not be revealed in the meantime.

They say a court in the US state of Georgia ordered a medical examiner to seal the results.

The daughter of famous hip-hop musicians; Bobby Brown and Whitney Houston died 22 years of age at a hospice on 26 July, six months after she was found unresponsive in a bath in her Atlanta flat.

She died at a Los Angeles hotel on the eve of the Grammy Awards ceremony in 2012.

In a statement, the Fulton county medical examiner said Bobbi Kristina's post-mortem results would not be publicly released on the order of the Fulton county superior court.

"The Fulton County medical examiner has classified the cause and manner of Bobbi Kristina Brown's death," it said.

Bobbi Kristina was the only child of singer Whitney Houston and her father was R&B singer Bobby Brown.

She was buried in August at the Fairview cemetery in Westfield, New Jersey, next to her mother.

Bobbi Kristina Brown began performing with her mother in 1999, singing duets of My Love is Your Love and recording Little Drummer Boy for a holiday album in 2003.