MILAN, Italy - Police have searched the homes of several women who attended ex-Premier Silvio Berlusconi's famed "bunga bunga" parties as part of an investigation into alleged witness tampering during the billionaire's sex-for-hire trial.

An appeals court last July acquitted Berlusconi of paying a 17-year-old girl, Karima el-Mahroug, better known as Ruby, for sex on the grounds that he was apparently unaware of her age when she attended the sex-fuelled parties.

Over the course of that trial, a new investigation began concerning allegations of witness tampering with some of the other "bunga bunga" participants. Berlusconi, his lawyers, el-Mahroug and several women are under investigation but haven't been charged.

On Tuesday, police searched the homes of several of the women and the home of el-Mahroug's lawyer, according Milan prosecutor Edmondo Bruti Liberati.