People who have had treatment at an alternative cancer clinic in Germany are running a ‘concrete health risk’ Dutch, German and Belgian police said in a joint statement on Friday.

‘A far-reaching medical investigation still has to show exactly what happened but there is currently a concrete health risk for patients who have been treated at this clinic,’ the Dutch police statement said.

Earlier a 43 year-old breast cancer sufferer died at the clinic and it has since become clear that a 55 year-old man from the Netherlands and a 55 year-old woman from Belgium also died recently after being treated there. Two Dutch women remain in hospital after being treated at the clinic, the police statement said.

People from the Netherlands who have received treatment at the clinic are being advised to contact the police.

The clinic’s director, Klaus Ross, denies any wrongdoing and has said he would cooperate with police enquiries. ‘Alternative medicine is complementary. We always advise our patients to explore regular treatment first,’ Ross said.