Jacobus van Nierop is a Dutch dentist who mutilated patients in France. In crimes from 2009-2012, he attacked over 100 patients in the guise of routine treatment. In March 2016 he was convicted of fraud and aggravated assault against vulnerable persons, receiving an eight-year term. The press dubbed him The Monster Dentist.
van Nierop, who used the name Mark, arrived in the rural town of Château-Chinon in 2008. As the area struggled to attract health professionals, locals were delighted and he set up a dental practice.
He became known as a hard worker and a friendly, approachable figure. He was also known locally for his flamboyant style, driving a large 4x4, keeping a big dog, and puffing on cigars.
However, van Nierop rapidly began performing painful and pointless work. He had twin motivations; fraudulently charging for the work against clients' insurance, and sadistic joy in causing pain and suffering. He would knock patients unconscious and pull out multiple teeth, often causing abscesses and even breaking jaws in the process.
Patients received multiple injections of anesthetic and were left bleeding heavily for days afterward. Some were worked on several times in quick succession over a period of a week.
In 2013 a teacher named Nicole Martin formed a victims' group to persuade authorities to investigate. Martin suffered severe abscesses and lost multiple teeth. The group quickly amassed 120 members, and in June that year police arrested van Nierop.
van Nierop went on the run before he could face trial, which was originally due in December 2013. In September 2014 he was tracked down to New Brunswick, Canada, and arrested. After extradition to France, he was sent to a psychiatric hospital and evaluated after he complained of mental troubles.
He was found to have "narcissistic tendencies" and one expert ruled him unfit for trial. Another, however, found him to understand fully his actions. The court took the latter view and he was convicted. At no stage in legal proceedings did he admit or deny guilt, as French law did not require him to plead.