Whitney Houston Police Seek Search Warrant in Death Investigation

2/11/2012 7:59 PM PST

Beverly Hills police have sealed off the room where Whitney Houston died and will not enter until they obtain a search warrant ... TMZ has learned.

Law enforcement sources tell us ... the police want to conduct a thorough search of the hotel room, but are exercising caution by getting a warrant. We're told one thing police are interested in is whether drugs are present in the room. 

Although police could seize items in plain view, we're told they want a top-to-bottom search of the room.

Beverly Hills cops entered the room in response to the 911 call when emergency workers gave Whitney CPR, but we're told aside from a cursory look around the room ... they conducted no search.