According to reports, the arrests were made at the request of the Anti-Mafia Directorate regarding the development of the 64.6MW Nebrodi and 47MW Alcantara-Peloritani wind farms. The projects came online last year.
The charges include allegations that permits were held up to force the developer to use preferred suppliers and a failure to implement the criteria set out by the developer. Additionally, it is believed the materials were of a poor quality.
The Nebrodi wind farm consists of 76 Gamesa G52- 850kW wind turbines. According to Windpower Intelligence, Iberdrola partnered with Italian company Api Nova Energy, part of Grupo Empresarial, to build the project. It said Alcantara was developed by Societa Energie Rinnovabili, which is 50% owned by Iberdrola.
This is not the first time Italian anti-mafia police have made arrests related to wind power development.
There is an ongoing investigation into mafia involvement in the 96MW Isola Capo Rizzutto wind farm in the southern Italian region of Calabria.
The wind farm - one of Italy's largest - continues to be operated by a court-ordered administrator after being confiscated by judicial authorities last July, an arrangement that could potentially last for years.
Investigators believe the Arena clan, part of the Calabrian 'Ndrangheta criminal association, invested in the wind farm through the use of shell companies and frontmen.
In 2010, Italian environmental association Legambiente issued a report looking at illicit activities in the sector and claimed wind was relatively untainted by the mafia.
It was designed to set the record straight after months of media reports closely associated the country's wind business with criminal activity.