Investigators from the judicial police general crime department carried out searches on Monday and Tuesday at the residences of those accused of having embezzled funds from the CNS.
The searches were ordered by Luxembourg's investigating magistrate.
Four people were arrested, one of whom was a 52 year old CNS employee, suspended since the misdeeds were discovered at the start of the year. Three men associated with the employee were also arrested.
The four suspects have been charged with theft and fraud at the expense of the National Health Fund, with the embezzled amount estimated to be two million euros. They came before an investigating judge, who ordered their detention on remand.
A spokesperson for the judiciary said the investigation would continue.
More details to come.
