By Crispian Balmer
ROME (Reuters) - Italian police arrested 50 people on Thursday and placed a prominent centrist politician under investigation in a crackdown on the 'Ndrangheta mafia that prosecutors say lays bare its efforts to launder cash and buy influence.
The 'Ndrangheta is based in the southern region of Calabria, the toe of Italy's boot, and has surpassed Sicily's more famous Cosa Nostra to become the most powerful mafia group in the country -- and one of the largest crime gangs in the world.
"This investigation makes clear what we have been saying for decades. The 'Ndrangheta shoots less and has more and more ties with business and politics," said prosecutor Nicola Gratteri, who last week launched one of Italy's biggest mob trials.
Among those placed under investigation was Lorenzo Cesa, head of the small UDC party, who was in the national spotlight last week after he rejected overtures from Prime Minister Giuseppe Conte to join the ruling coalition, which has lost its absolute majority in parliament.
Gratteri said Cesa was suspected of offering to procure contracts for the 'Ndrangheta in return for favours.
Cesa, who is a member of the European Parliament representing southern Italy, denied the accusation, but said he would resign as head of the UDC "given this particular moment our country is going through".
It was not immediately clear if his departure would lead to a rethink within the UDC over Conte's request for backing.
The police in Calabria said they carried out more than 250,000 phone taps and secret recordings which helped show how the 'Ndrangheta had used an array of front companies to launder money and generate false invoices for tax scams.
Warehouses were rented, but left empty, and trucks sent in for simulated offloading and loading operations, the police said.
Gratteri said the lynchpin was a local man who had close ties with police, politicians, businessmen and various 'Ndrangheta clan. He was detained and it was not immediately possible to obtain comment from him.
"During the search of his house, (police) found hundreds of millions in cash which they have not yet finished counting, dozens of Rolexes and luxury cars," Gratteri told reporters.
The trial that began last week in Calabria is of 355 suspected 'Ndrangheta gangsters and their white-collar associates.
The last time Italy tried hundreds of alleged mafiosi simultaneously was in 1986 in Sicily in a case that represented a turning point in the fight against Cosa Nostra, marking the beginning of that group's sharp decline.
(Reporting by Crispian Balmer, Editing by Timothy Heritage)