Four counts of manslaughter along with other charges, including causing grievous bodily harm, were leveled against the operators of the clinic in Wegberg.

Der Spiegel said the small St. Antonius clinic was alleged to have conducted unauthorized surgeries and suffered from lax hygiene. The conditions allegedly contributed to the deaths of seven patients.

Among the allegations was the use of lemon juice to sterilize wounds and removal of healthy gall bladders without the patient's permission.

Arnold Pier, the clinic's managing director and head doctor, was arrested last week. Eight other doctors were expected to be picked up later this week, Der Spiegel said.