Police in northern Greece said Wednesday they have broken a gang that had found ways of hacking, or otherwise tampering with, domestic and industrial electricity meters to show much lower readings and sold their services to about 100 people, costing power companies millions of euros.

A police statement said the three alleged gang members who were arrested Tuesday in Thessaloniki had been active since 2017 and had made at least €371,000 from individuals and companies who paid subscriptions to have their electricity bills fraudulently reduced on a regular basis.

The overall cost to power providers was around €9.2 million.

Power costs have risen drastically in Greece in recent years, amid an overall cost-of-living crisis.

The gang’s customers included energy-intensive businesses such as petrol stations, restaurants, internet cafes, meat, food and milk packaging plants and olive oil presses, the statement said.