The coroner who oversaw the inquest into the death of singer Amy Winehouse has resigned after her qualifications were questioned, officials said Wednesday — raising the possibility the investigation may have to be held again.

Winehouse's relatives said they were still absorbing the implications of the news and were seeking legal advice.

In October, Suzanne Greenaway had ruled that the soul singer had died from accidental alcohol poisoning.

Greenaway had been appointed an assistant deputy coroner in London in 2009 by her husband, Coroner Andrew Reid. But she resigned in November after authorities learned she had not been a registered U.K. lawyer for five years as required. She had practiced law for a decade in her native Australia.

"I appointed my wife as an assistant deputy coroner as I believed at the time that her experience as a solicitor and barrister in Australia satisfied the requirements of the post," he said in a statement Wednesday. "In November of last year it became apparent that I had made an error in the appointment process and I accepted her resignation."

Greenaway oversaw 12 inquests in Camden, the north London borough where Winehouse lived, and others in eastern London.

Reid said he was "confident that all of the inquests handled were done so correctly" — but offered to hold the inquests over again if the families of the deceased wanted it.

Winehouse's family said it had not yet decided what to do. In a statement, the family said it was "taking advice on the implications of this and will decide if any further discussion with the authorities is needed."

A security guard found Winehouse dead in bed July 23 at her home in the north London neighbourhood of Camden. The 27-year-old singer, known for her beehive hairdos and multiple Grammy-winning album Back to Black, had battled drug and alcohol addiction for years.

At the October inquest, Greenaway delivered a verdict of "death by misadventure," saying the singer suffered accidental alcohol poisoning when she resumed drinking after weeks of abstinence.