BERLIN (Reuters) - German police and customs officers searched 140 properties in western Germany and arrested eight people on Tuesday as part of an investigation into organized illegal work in the construction industry.

Prosecutors said they believed the suspects had created a complicated network of companies, using bogus invoices to evade paying social security contributions and taxes on a large scale.

“The suspects are accused of using a network of sham companies to create bogus invoices for several hundred construction firms in (the German state of) North Rhine-Westphalia,” said Armin Rolfink, President of Germany’s central customs authority.

He said the illegal turnover totaled some 48 million euros ($59.7 million) plus lost taxes and social security contributions of about 38 million euros.

“When you think about black labor, what springs to mind is a cleaner paid cash in hand or other small businesses that are a bit liberal with their taxes. What we have here is nothing like that,” Wuppertal public prosecutor Wolf-Tilman Baumert said.

“These are highly professional criminals who can expect punishment if they are convicted. The legal penalty is a minimum six months custodial sentence per crime totaling up to 10 years,” he added.