The family of Amy Winehouse has revealed toxicology reports showed there were "no illegal substances" in her body at the time of her death.

The 27-year-old singer was found dead at her north London home last month. Her family said the reports showed alcohol was present in her body, but it is not yet known if it contributed to her death.

Winehouse's father, Mitch Winehouse, had previously said she had "conquered her drug dependency" before she died.

"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," the family said in a statement on Tuesday.

"Results indicate that alcohol was present, but it cannot be determined as yet if it played a role in her death.

"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."

Winehouse was discovered by her bodyguard at her Camden flat at around 4pm on Saturday 23 July.

An initial postmortem examination proved inconclusive, and an inquest was opened and adjourned with no cause of death given.

At her funeral on 27 July, Mitch Winehouse said she had recently "completed three weeks of abstinence", adding that she had told him: "Dad, I've had enough of drinking, I can't stand the look on your and the family's faces any more."

He had announced that he would set up an Amy Winehouse Foundation in memory of the singer and was flooded with donations, only to have to put plans on hold last week after a "dickhead" beat the family to registering the website domain name.

He had hoped the foundation would be able to "help all children in need", but said he was having to return all donations.

"We all have to bombard the tabloids' websites to put pressure on this dickhead who stole our foundation name," he wrote on Twitter. "This person was offering to sell [the] name on [a] website."

Amy Winehouse had fought a well documented battle with drink and drugs. In the month before she died, she was booed off stage in Belgrade on the first night of what had been billed as a 12-show comeback tour. The dates were later cancelled.

The singer rose to fame in 2003 with the release of her debut album, Frank. Her second and last album, Back to Black, was released in 2006, reaching No 1 in the UK.

In the week after her death, the album again topped the UK chart as fans mourned the singer.