Whitney Houston's death certificate has been filed in Los Angeles County.

The document obtained by TMZ shows that the singer's cause of death is still unknown.

The 48-year-old I Will Always Love You singer was found dead in the bathtub of the Beverly Hilton hotel on Saturday after a long battle with drugs.

The document states that the immediate cause of death is "deferred" and the manner of death is still "pending investigation."

The autopsy on Whitney's body was completed on Sunday but results from toxicology tests will take another four to six weeks to come back.

The site also reports that Whitney will be laid to rest in the burial plot right next to her father's grave at Fairview Cemetery in New Jersey after Saturday's funeral.

John Houston died in 2003 and family sources told the site that she wanted to be buried next to her beloved father.

Meanwhile, Bobbi Kristina's godmother, CeCe Winans has promised to be "very involved" in the teen's life.

CeCe lives in Nashville with her husband and children but said she is praying regularly for her long time friend's daughter. They had a hit with their song Count on Me from the Waiting to Exhale soundtrack in 1996.

The gospel singer's brother, Rev. Marvin Winans, will be the one to deliver the eulogy at Whitney's funeral this weekend which will be a private memorial under the request of the late performer's family.