Updated

A Rome court on Thursday convicted dozens of defendants in a wide-ranging corruption trial that revealed a system of kickbacks and intimidation to gain control of city contracts, but acquitted all of the defendants on key charges of mafia-style association.

The trial was the first in Italy to unite allegations of corruption with the trappings of organized crime, and the court's across-the-board rejection of the mafia-style allegations was a blow to prosecutors' case, touted by Italian media as "Mafia Capital."

The court gave the highest sentence to the alleged ringleader, Massimo Carminati, who was handed 20 years in jail — shy of the 28 sought by prosecutors. Just one of the 46 defendants, a gas station operator with alleged Mafia ties, was acquitted.

"They certified that 'Mafia Capital' doesn't exist," Ippolita Naso, Carminati's defense lawyer, told reporters after the verdict.

Prosecutors say rampant corruption, which involved the management and supply of migrant shelters, sanitation agencies, parks maintenance and other municipal services, dated back years. The allegations implicated officials from both left-leaning and right-leaning parties, as well as bureaucrats and outside go-betweens.

The Codacons consumer group estimated that the collusion on city contracts cost Roman citizens an estimated 1 billion euros (about $1.1 billion.)

The wrongdoing predates the tenure of Mayor Virginia Raggi, who was present for the verdicts, representing the city as an injured party.

"It is a very deep wound in the fabric of the city of Rome," Raggi told reporters. "What was clearly ascertained today is that there was a criminal association that was able to control the political choices of this city and we are paying for the damage, we see it every day."

Prosecutors have vowed to appeal the verdicts.