Toxicology results of singer Amy Winehouse has revealed that no illegal drugs were found in her system making her death a mystery, according to a statement made by her spokesman.

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 statement read.

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

Mitch Winehouse, Amy's father, was pleased that his troubled daughter didn't take illegal drugs before her death, although she had drunk alcohol. But whether the drinking factored into her death is unknown.

This doesn't make me feel the loss of my daughter any less, but we are pleased to be able to set the record straight to a certain extent, said Mitch told Britain's The Sun.

According to addiction experts and toxicologists, the toxicology results did little to solve the mystery of Winehouse's death.

Combinations of perfectly legal substances can be lethal, said Jeremy Clitherow, a community pharmacist who specializes in addiction.

You would have to look at the wording (of the toxicology report). You'd have to see the report rather than the paraphrased version. We can't speculate.

At Winehouse's funeral, Mitch said her daughter had conquered her drug addiction three years ago but was struggling with a drinking addition. According to an unnamed family source, Winehouse's relatives suspected alcohol withdrawal was her death cause. She stopped drinking suddenly, rather then gradually. But her toxicology results show that alcohol appeared in her system when she died.

It is very unusual for people to die from alcohol withdrawal, Clitherow said. You can get delirium tremens (DTs), but normally you survive.

Winehouse, a 27-year-old British singer, was found dead in her London home on July 23. She possessed a unique and soulful voice, which helped her gain numerous music industry awards. However, during her lifetime, Winehouse battled personal demons and struggled with drug and alcohol addiction. Her self-destructive behavior, including violent mood swings and self-harm, also became regular topics in the tabloid from 2007 until her death.