Naples, February 15 - Italian police on Friday arrested 12 alleged members of the Neapolitan Camorra mafia in connection with a probe into a suspected protection racket on hospital laundry operations in the Naples area. The powerful Naples hinterland Casalesi clan - the group that forced writer Roberto Saviano into police protection - teamed up with two of the southern Italian city's main crime families, the Missos and the Lepres, police said, to prey on one of the Campania region's main laundries, the American Laundry Ospedaliera (ALO). The three groups had extorted money from ALO's laundering of hospital linen and other materials since it was set up in 2000, police said. ALO was forced to pay 'pizzo' whacks of 8,000-12,000 euros at Christmas, Easter and the mid-summer Ferragosto holiday, putting it into "a severe financial crisis" and threatening 400 jobs, police said. The Casalesis' part of the operation was led by jailed boss Francesco Bidognetti, nicknamed 'cicciotto 'e mezzanotte' (Midnight Fatty) with the help of a lieutenant on the outside, Alessandro Cirillo aka 'o sargente' (The Sergeant), police said. The Casalesi crew coordinated with the Naples mobsters thanks to Luigi Guida, whose gang tag was 'o drink' (The Drink), police said. A total of 26 people have been placed under investigation.