Umberto Bossi
Umberto Bossi, leader of Italy's separatist Northern League, resigned on Thursday. Reuters

Controversial Italian politician Umberto Bossi resigned as the head of the separatist Lega Nord, or Northern League, on Thursday in the heat of a corruption scandal.

Bossi left the political party he founded in 1991 to better defend and protect the image of the movement and of his family in this delicate situation, said a statement from the league. Prosecutors have accused Bossi of using taxpayer money for private expenses such as vacations and cars for his sons. His party is also under investigation for embezzlement, fraud, and money laundering.

A police warrant states that party treasurer Francesco Belsito used public money to support the expenses of the Bossi family -- and Northern League money was allegedly used to pay for Bossi's medical treatment in 2003 and for home renovations, according to Agenzia Giornalistica Italia.

Advocating secession of Italy's north from the rest of the country, the league has nonetheless taken part in national governments, and it was a major partner in Silvio Berlusconi's ruling coalition until the former prime minister resigned in disgrace last November. The league had risen to prominence wth a reputation built on attacking government corruption. Now its international investments are being checked for possible connections to organized crime.

Berlusconi, who is no stranger to scandal, called Bossi's resignation a shock to the system. To some, the current scandal is reminiscent of the Mani pulite or Clean Hands investigations of the early 1990s that brought down the Christian Democratic Party that had ruled Italy since the end of World War II.

In Bossi's absence, the league will be run by a triumvirate made up of three top party figures: former ministers Roberto Calderoli and Roberto Maroni, and a member of parliament from the Veneto region, Emanuela Dal Lago. Some feel the future of the party is unsure.

The Northern League is going to melt down, Italian political analyst and pollster Renato Mannheimer told Reuters. The League is based on Bossi, and he won't easily be replaced.

Although he no longer heads the party, the outspoken Bossi -- known for his salty language and disdain of Italy's political establishment -- is not yet prepared to leave the Northern League altogether. He was named party chairman on Friday and will still take part in certain meetings and proceedings.

Nobody asked me to resign. I decided to myself, because I was in the way, but the fact that I resigned doesn't mean I'm disappearing from the scene, Bossi told La Padania, the party's official newspaper. They are sorely mistaken. I'm staying in the Northern League, whether as a grassroots activist or secretary, I will always be ready to fight for the cause.

This week, Italian daily Corriere Della Sera detailed the investigators' findings, which included an incident in which a businessman hid a large sum of cash inside a hat that was handed off to Belsito, the party treasurer.

Two businessmen, Stefano Bonet and Paolo Scala, are also being investigated over investments made on behalf of the Northern League in Tanzania, and police are looking into Belsito's possible connections with the 'Ndrangheta, a powerful criminal organization based in Calabria in southern Italy.