Rome mayor refuses to resign.

Police arrested five people on 9 June as part of an ever-widening investigation into a mafia syndicate allegedly operating within Rome's city administration.

The five, most of whom are under house arrest, include the head of the technical office of Rome's sovrintendenza ai beni culturali, which manages the capital's archaeological sites, and legal representatives of three companies involved in the restoration of the city assembly hall where the city council convenes.

The Giulio Cesare hall was inaugurated in September 2010 by then-mayor Gianni Alemanno, who is among the more than 100 public officials and business figures being investigated as part of the so-called Mafia Capitale case.

Another 20 people were placed under investigation on 9 June on suspicion of crimes including bid-rigging, racketeering, aggravated fraud, issuing false invoices, and tax evasion.

The cultural heritage official, Maurizio Anastasi, under house arrest is suspected of having given preferential treatment to businessman Fabrizio Amore, who is also under investigation for tax fraud, to win the €2.5 million restoration contract.

Marino, who has so far refused calls from opposition parties and groups for his resignation, is supported by Italian premier Matteo Renzi who said recently that the current mayor could not be held responsible for a corrupt system which was already well-established by the time Marino took office two years ago.

The Mafia Capitale investigation began in December 2014 and centres mainly on the embezzlement of funds destined for emergency housing for immigrants and camps for Roma people, but also includes other sectors such as waste management, recycling and parks maintenance.

The case has seen dozens of public officials, business people and politicians from all sides of the political spectrum, arrested for alleged mafia activity, including the 44 arrests made in Lazio, Abruzzo and Sicily on 4 June.