The cause of singer Whitney Houston’s death is still unknown. The website TMZ is reporting that Houston was found in the bathtub of her hotel room at the Beverly Hilton and had been taking Xanax, which is used as to treat anxiety and depression and can sometimes cause severe sedation. There is no evidence that any illegal drugs were in Houston’s hotel room, though TMZ reports that there were several pill bottles. Meanwhile, Grammys producers are scrambling to pay homage to the singer at tonight’s show. Jennifer Hudson has joined the tribute lineup.