Sonny Bono was clubbed to death by hired hitmen, according to an extraordinary tabloid expose based on the investigations of a former FBI agent.

Cher's ex-husband's death was officially recorded as a tragic "skiing accident," with family and friends apparently satisfied he died after colliding with a tree on the piste in Nevada in January 1998.

However, former FBI agent Ted Gunderson - who has spent the last ten years investigating the case - claims top officials linked to an international drug and weapons ring arranged a hit on the singer-turned-politician because they feared he was about to expose them.

He tells America's Globe: "It's nonsense for anyone to now try to suggest that Bono died after crashing into a tree. There's zero evidence in this autopsy report...to show such an accident happened.

"Instead, there's powerful proof he (Bono) was assassinated.

"This was an evil plot that was carried out to almost perfection by ruthless assassins."

It's Gunderson's opinion that the experienced skiier was ambushed on the slopes by hired hitmen, who beat him to death and then staged a tree collision.

Despite the seemingly far-fetched nature of the claims and the fact that they appear in the Globe, Gunderson's findings have reportedly been backed by top forensics experts.

He is now calling for the authorities to open a homicide investigation.