Nick Gordon and Bobbi Kristina Brown Nick Gordon and Bobbi Kristina Brown

Police have launched an investigation into Bobbi Kristina Brown's drowning, TMZ reports.

The daughter of Whitney Houston and Bobby Brown was found unconscious in a bathtub on Saturday and has remained on life support ever since.

Law enforcement sources told the website that Bobbi Kristina has unexplained injuries and that police are looking into a possible altercation between Bobbi Kristina and her partner Nick Gordon that may have occurred over an hour before she was found.

Bobbi Kristina Brown's family involved in hotel brawl

Max Lomas, the friend who discovered Bobbi Kristina in the bathtub, said he arrived at around 9 a.m. Saturday and spent time with Gordon. He said there was no sign of Bobbi Kristina. Lomas described Gordon as uninterested in her whereabouts and said that Gordon claimed she was in the bedroom.

Little over an hour later, a cable man arrived at the house and said he needed access to the bathroom. That is when Lomas claims he discovered Bobbi Kristina in the bathtub and called for Gordon, who administered CPR.

According to Lomas, Gordon also allegedly cleaned up the house and removed blood stains.