Fifteen volunteer firefighters have been arrested in Sicily on suspicion of starting wildfires and reporting non-existent blazes so they could earn €10 (£9) an hour for putting them out.

Police in Ragusa province, in the south of the Mediterranean island, said the fire department became suspicious when it emerged that the auxiliary brigade had responded to 120 incidents compared with just 40 tackled by other volunteer teams over the same period.

The brigade commander, a refrigeration technician identified as DDV, was deemed dangerous enough to be held under house arrest, the Ansa news agency reported, because he was suspected of continuing to start fires after others had stopped.

Most of the remaining team members, whose private phone calls were recorded as part of the investigation, have since admitted calling the 115 emergency number or getting friends or relatives to do so.

In collusion with some of the brigade, DDV allegedly left the station in his van, lit fires or made false emergency reports, then came back and waited to be called out to deal with it. He showed “a sharp criminal ability and ... no fear about the consequences of his behaviour”, police said.

Investigators added in a statement that on one occasion, the commander “even spoke of wanting to set off a bomb” at the station in order to “take the money available if the emergency vehicles needed to be repaired”.

Most of the team were under investigation for fraud, with several also suspected of arson, Ansa said. The island is plagued by fires in summer and auxiliary firefighters are paid €10 an hour by the state to help extinguish them.

Sicily, along with much of southern Italy, is experiencing soaring temperatures and a prolonged drought. In some areas strong winds have fanned wildfires, some of which have been blamed on arsonists.