Boyfriend under investigation in Bobbi Brown's drowning: Media

Bobbi Kristina Brown attends the opening night of The Houstons: On Our Own in New York, in this file photo taken on Oct 22, 2012. -- PHOTO: REUTERS
Bobbi Kristina Brown attends the opening night of The Houstons: On Our Own in New York, in this file photo taken on Oct 22, 2012. -- PHOTO: REUTERS

WASHINGTON (AFP) - Police have opened a criminal investigation of the boyfriend of Bobbi Kristina Brown, US media reported, one week after the 21-year old daughter of late singing legend Whitney Houston was pulled unconscious from a bathtub.

CNN and TMZ reported Saturday that a criminal investigation has been launched against Nick Gordon, who reportedly said that he found Brown non-responsive in the bathtub of their home near Atlanta, Georgia.

The incident appeared to have eerie echoes of Houston's fatal accidental drowning nearly three years ago in a Los Angeles tub.

But news reports said Saturday that Brown, who is in the hospital in a medically induced coma, sustained unexplained injuries prior to the incident.

The reports, which provided no details as to the nature of the injuries the young woman is said to have, say authorities reportedly are also suspicious because she was found face down in the bathtub.

TMZ wrote that it was told by multiple sources that there is a history of violence between Brown and boyfriend Gordon and that police are looking into a possible altercation more than an hour before Brown was found.

Reports call Gordon Brown's boyfriend, saying there are no official documents showing they were ever legally married, although the couple presented themselves in public as husband and wife.

Singing star Whitney Houston died in February 2012 when she was found in a bathtub at the Beverly Hilton Hotel in Los Angeles on the eve of the music industry's annual Grammy Awards show.

Coroners concluded that the singer died by accidental drowning, with cocaine use and heart disease as contributing factors.