Italy's Silvio Berlusconi may face greatest challenge yet with teen prostitution inquiry

A day after losing his immunity from criminal prosecution, Italy's flamboyant prime minister has been notified that he is under investigation for having an alleged affair with a minor – and then using his political muscle to try and cover it up.

Silvio Berlusconi today received a letter from the Tribunal of Milan notifying him that he has been under investigation since Dec. 21 for “underage prostitution” and “abuse of power,” according to Italy's biggest daily newspaper Corriere Della Sera. He was invited to appear for questioning later this month.

While Mr. Berlusconi has faced numerous legal challenges in recent years, the latest investigation may well be his greatest hurdle yet. Both accusations relate to the prime minister's involvement with Karima "Ruby" El Mahroug.

The woman of North African origin was 17 years old when the 74-year-old prime minister allegedly paid for her sexual services early last year. Prostitution is permitted in Italy, although brothels are illegal. The age of consent for sex is 14, but exploiting or aiding prostitution of minors under 18 is a crime. Ms. Mahroug has since turned 18.

The accusation for "abuse of power" stems from Berlusconi allegedly helping Mahroug get out of jail in May. While the young woman was in police custody for a case of petty theft, the billionaire businessman allegedly made a phone call to Milan prosecutor Annamaria Fiorillo asking her to release the girl immediately.

Ms. Fiorillo, in a recent interview with la Repubblica daily, recalled that Berlusconi claimed Mahroug was “[Egypt's president Hosni] Mubarak's niece.” To this the prosecutor had answered: “Of course, and I am queen Nefertiti."

Mahroug was subsequently released from jail.

Revelation of the ongoing investigation comes a day after the Constitutional Court overruled a July 2008 law that granted the prime minister immunity from criminal prosecution. For the past 2 and 1/2 years, the immunity law has shielded him from three separate corruption trials. But it has also cost him political capital.

Opposition within his Freedom Party to the immunity law caused the ruling coalition to split in late 2010, spurring a no-confidence vote in December that Berlusconi narrowly survived.

This is not the first time Berlusconi – who has admitted "I love life, I love women!" – is accused of improper relationships with young women. Rumors swirled in 2009 of an alleged relationship with Noemi Letizia, then 17. The case sparked a media hype throughout the country, but it did not carry any legal implication, nor did it have any political consequence. Since then, however, Ms Letizia has become a minor celebrity.

The US State Department, according to confidential cables recently released by WikiLeaks, has described Berlusconi as someone whose “frequent late nights and penchant for partying hard mean he does not get sufficient rest.”