Police entered the home of the 24 year-old singer yesterday (November 8). Winehouse and her husband, Blake Fielder-Civil, were not home at the time.
It is not clear yet why Winehouse is being targeted, although police admit that, "Investigations are ongoing."
During the same investigation, four men ranging in ages from 19 to 25 were arrested. Winehouse, who was arrested in Norway for marijuana possession, performed last week at the MTV Europe Music Awards. Winehouse sang her song Back to Black before winning an award.
A spokesperson for Winehouse refused to comment on the police search.