Police raided Amy Winehouse's London home. The singer's spokesman said she was not there at the time and that drugs were not involved.
British media said the raid was related to the arrest of Winehouse's husband and several other men on suspicion of trying to pervert the course of justice.
Photographs printed Friday in British newspapers showed police officers using a crowbar to force open the door of the singer's home in Camden, north London.
"The only thing I can tell you is that it has nothing to do with drugs and that Amy is fine and she has not been charged or arrested," spokesman Shane O'Neill said.
The Metropolitan Police said there had been "police activity" at the house on Thursday as part of an investigation into allegations of perverting the course of justice.
British media reported that the investigation concerned Winehouse's husband, Blake Fielder-Civil, who is due to stand trial next week on charges of assaulting a barman.
Police said four men - two aged 25, one 22 and one 19 - were arrested in connection with the investigation. The force would not confirm that Fielder-Civil, 25, was among them, but the Daily Mirror ran a picture of Winehouse kissing Fielder-Civil, who was in handcuffs. The newspaper said the pictures were taken as he was arrested Thursday.
A fifth man, aged 36, was arrested Friday in central England.
Retro soul singer Winehouse has won worldwide acclaim for her second album, "Back to Black," but has also made headlines through erratic behavior, health fears and reports of heavy drug use. In August she spent time in rehab and canceled a series of dates in Britain, the United States and Canada.
Last month Winehouse and Fielder-Civil were arrested in Norway and fined 500 EUR(US$715) for possession of marijuana.