Anti-mafia police arrested Bidognetti on Friday for his alleged involvement in the attempted killing of two relatives of an alleged informant inside the suspected Casalesi mafia clan, the Italian news agency ANSA reported.

Bidognetti's father, Francesco, is currently in police custody along with other suspected Casalesi heads.

Police say they have also issued an arrest warrant for Giuseppe Setola, the reputed leader of the clan's alleged hit squad.

Naples anti-Mafia official Franco Roberti said Setola, whose alleged squad is suspected in nearly 20 deaths since May alone, is likely a top official in the suspected crime family.

''Setola is without doubt the brains behind the Casalesi campaign,'' Roberti told ANSA.

''We are working to flush him out. The circle is closing around him."