Exchange bureaus suspected of laundering millions in drug profits were used by police to convert foreign currency seized from criminals, Nieuwsuur has reported.

Police confirmed they have had a contract with Suri-Change since 2016 which has been used to change several hundred thousand euros’ worth of cash into euros, netting the company “tens of thousands” in commission.

Three months ago police raided the head office of Suri-Change in Rotterdam and arrested the 73-year-old owner and his two sons. They also impounded 42 properties worth a total of €25 million.

One of the sons and two other men from Rotterdam are also suspected of laundering drugs money on the international financial markets. All the suspects apart from the owner are currently in custody.

Four branches of Suri-Change in Amsterdam and The Hague have since been closed after they were targeted in bomb attacks.

Police briefly suspended their contract with Suri-Change in 2017 during an earlier investigation into money laundering. “We halted it for several months, but there was insufficient evidence of criminal activity and the licence was not withdrawn,” a spokesman told Nieuwsuur.

The seven-year contract is due to expire on July 1.

The lawyer for the company, Ayse Çimen, said that the contract was evidence that the police regarded Suri-Change as a reputable business.

“If justice officials thought Suri-Change was so shady, why did police do business with the company for years?” she said.