Quarto, January 21 - Rosa Capuozzo told a news conference on Thursday that she was resigning as mayor of the town of Quarto, near Naples. Capuozzo was elected on a 5-Star Movement (M5S) list but was subsequently ejected from the anti-establishment group after initially refusing to step down following allegations of mafia infiltration of her executive. The case was an embarrassment to the M5S, which prides itself on not being tainted by the corruption scandals that have frequently hit Italy's established parties. Capuozzo said she had told M5S bigwigs in November about threats she allegedly received from fellow councillor Giovanni De Robbio, who is allegedly linked to the the Campania mafia, the Camorra. The M5S has denied this, saying it was only informed in December and expelled De Robbio days after. "I resign from the post of mayor," Capuozzo told reporters. "The decision was dictated by the lack of the necessary numbers (of councillors) needed to govern. "It's an act of responsibility for Quarto, not a surrender". She added that she "felt abandoned" by the M5S. "It's a political defeat and it's also a victory for the Camorra," she said. Premier Matteo Renzi's centre-left Democratic Party (PD) was also critical of M5S handling of the case. "The M5s encountered the Camorra in Quarto and instead of fighting it, they turned the other way and fled," Stefano Esposito, a PD Senator and member of the parliamentary anti-mafia commission, said on his Facebook page. Capuozzo added that she does not intend to stand again, not even on a civil list separate from the M5S. Capuozzo's husband Ignazio Baiano is under investigation for alleged false declarations and alleged breach of construction regulations, ANSA sources said this week. This may have been used in an attempt to blackmail Capuozzo by De Robbio, the sources said. Rosy Bindi, the head of the anti-mafia commission, has sent the documentation relating to a hearing Capuozzo had before the commission on Tuesday to Naples prosecutors after identifying areas that needed to be further examined, ANSA sources said.