By NBC News' Claudio Lavanga

ROME – After months of speculation over the involvement of Italy’s Prime Minister Silvio Berlusconi in a prostitution ring made up of television starlets, runaway minors and social climbers, Italian investigators have formally requested a speedy and immediate trial for the embattled leader.

Investigators say the evidence that he paid for sex with an under-age Moroccan belly-dancer and used his influence to secure her release from police custody last May is so strong that they want to skip preliminary hearings and try him as soon as possible.

The decision by prosecutors came after details of the investigation, leaked to the media, have thrown Berlusconi’s government and his character into disrepute. The scandal has caused an uproar among Italian women, who organized demonstrations last Sunday against the culture of “sex for favors,” for which they say Berlusconi, 74, is partly to blame. 

Wiretapped phone conversations between some of Berlusconi’s house guests – sexy television starlets, suspected prostitutes, would-be stars, a faithful newscaster and a greedy talent scout – are meant to prove that the prime minister showered women with expensive  presents in exchange of sexual favors. While such behavior would have been at the very least inappropriate for a prime minister, it became a crime when it was revealed that one of the “party-goers” was a minor. In Italy, it's illegal to pay for sex with a woman under the age of 18.

Prosecutors claim that Karima El Mahroug, better known as “Ruby the Heart-Stealer,” had sex with Berlusconi when she was 17 years old. A previously unknown runaway belly-dancer born in Morocco, she became a household name last December when it was revealed Berlusconi took the trouble to personally secure her release from police custody by falsely claiming she was the daughter of Egyptian President Hosni Mubarak. 

And yet to the amazement of his allies and the demise of his critics, the scandal-prone prime minister’s popularity among voters was only slightly dented, and his political survival contributed to reinforce his aura of invincibility. His unparalleled ability to find last-minute support and reassure his allies about the stability of his government have made sure he survived a n¬¬¬¬umber of recent parliamentary sessions widely seen as votes of confidence.

Opposition politicians who were hoping Berlusconi would be ditched by an already divided coalition, and the thousand of Italians who in the last few days demonstrated across the country under the common slogan “Italy is not a brothel,” will now rest their hopes in the prosecutors.

Berlusconi’s lawyers say he did nothing improper and that prosecutors are actually “violating the constitutional norms.”

Italian judges now have five days to consider the prosecutors’ request to indict Berlusconi for an immediate trial – a decision that might seal the prime minister’s fate and Italy’s political future.

For more on the Berlusconi scandal, click here: Naked Emperor: One sex scandal too many for Berlusconi?