Beverly Hills Police Department are keen to question Whitney Houston's associate, Raffles Van Exel.
After the pop superstar was found lifeless in the bathtub of her Beverly Hills hotel room on February 11, the Los Angeles County Coroner ruled her official cause of death was accidental drowning due to the effects of heart disease and cocaine use.
However, police are now keen to speak with Mr. Van Exel - a member of the star's entourage - after he admitted to cleaning out the hotel room immediately after she passed away, allegedly removing vital evidence about Whitney's drug use from the premises.
A law enforcement source told RadarOnline.com: "Whitney's family, including her sister-in-law Pat Houston had absolutely no idea that Whitney was using drugs again. The family has been extremely cooperative and they have been told that investigators want to speak to Raffles Van Exel about allegedly removing evidence from Whitney's hotel room.
"The cops want to know who provided Whitney with the cocaine, but if someone tampered with the death scene, well, that could be against the law in California. Investigators have tried to make contact with Van Exel, but have been unable to do so.
"Since Van Exel is from Denmark, investigators assume that he may no longer be in the United States, and they very much want to talk to him."
Van Exel reportedly told Dutch newspaper De Telegraaf he cleaned out the 'I Will Always Love You' hitmaker's room after she died, removing clothes and belongings and sweeping the floor.
He said: "Someone had to do it. The room was empty."
Whitney's family recently admitted they were "saddened" to learn cocaine had played a part in her sudden death.
Patricia Houston, Whitney's sister-in-law and manager, said: "We are saddened to learn of the toxicology results, although we are glad to now have closure."