The cause of Amy Winehouse’s death is still uncertain. Toxicology tests have determined that “no illegal substances” were in the “Rehab” singer’s system at the time of her death last month.

“Toxicology results returned to the Winehouse family by authorities have confirmed that there were no illegal substances in Amy’s system at the time of her death,” stated her family. “Results indicate that alcohol was present but it cannot be determined as yet if it played a role in her death.”

The statement continued, “The family would like to thank the police and coroner for their continuing thorough investigations and for keeping them informed throughout the process. They await the outcome of the inquest in October.”

Amy Winehouse was found dead at her apartment in London at the age of 27.