Rome, December 17 - Former Italy and AC Milan midfielder Gennaro Gattuso is under investigation in relation to a new part of a long-running betting-related match-fixing probe in the northern city of Cremona, judicial sources said Tuesday.

Gattuso, a member of Italy's 2006 World Cup-winning squad, is suspected of criminal association and sporting fraud along with around 20 other people, including 10 former and current players, the sources said.

Another famous ex-pro, former Lazio and Milan player Cristian Brocchi, is among them.

"I'm angry and offended," said Gattuso, who won two Champions League titles and two Serie A crowns during his 1999-2012 stint with Milan.

"I'm serene and I'm going to clarify everything: I don't want to have stains on my career," added the ex-player, who has been out of work since being sacked as second-tier Palermo's coach in September.

"It's absurd and incredible because I don't know what they want from me. I wouldn't even know where to start fixing a match. Now we'll see what happens. I'm sure I'll clarify everything". Early on Tuesday police arrested four people in relation to the probe, including Salvatore Spadaro and Francesco Bazzani, two men who allegedly acted an intermediaries between players and international gangs involved in illegal betting.

The investigators are looking at alleged attempts to fix scores of matches, including around 30 in Serie A, stretching back to 2009.

They include Milan v Lazio in February 2011 and Lazio v Juventus in May 2011. Prosecutors said it cost hundreds of thousands of euros to fix a Serie A match and there was a risk that the results of this season's matches had been influenced. Furthermore, Cremona preliminary hearings judge Guido Salvini wrote in documents regarding the case that "it seems" a criminal organisation allegedly headed by Singaporean Tan Seet Eng had its sights set on fixing matches at next year's soccer World Cup in Brazil.

Tuesday's developments are the latest to have come from Cremona since its 'Last Bet' criminal probe went public in 2011.

Scores of people have been arrested in relation to it, including Lazio midfielder Stefano Mauri and former Italy internationals Beppe Signori and Cristiano Doni.

This led sporting prosecutors to look at a series of cases of betting-related match-fixing, which saw four sides starting Serie A last season with points deducted because of their players' involvement - Siena (-6), Atalanta (-2), Torino (-1) and Sampdoria (-1).

Many players and coaches were also given bans, including Juventus boss Antonio Conte, who last year served a four-month ban for failing to report a deal to fix a match during his time at former club Siena.

In 2006 Juventus were relegated and stripped of two Serie A titles for involvement in the Calciopoli match-fixing scandal.

That scandal regarded schemes to have compliant referees officiate some teams' matches.