Winehouse was arrested in December after being called to a police station. At the time, she was released on police bail and had been asked to return at a later date for further questioning.
Police said they cannot identify former suspects by name, but they did confirm that prosecutors planned to take no further action against a 24-year-old arrested in December on suspicion of trying to pervert the course of justice.
Meanwhile, Winehouse's husband, Blake Fielder-Civil, appeared in a London court Friday on charges of attacking a pub landlord and then later conspiring with him to withdraw as a witness at the trial.
Fielder-Civil spoke only to confirm his name and plead not guilty. He is due to appear again in April.
Winehouse didn't attend court because she was traveling to Paris to perform at a Louis Vuitton party, her spokesman said.
The singer won five Grammy Awards, including best record, best song and best new artist, in early February, but her musical success has been overshadowed by her tumultuous private life and public struggles with drugs and alcohol.