For the first time in years, the number of murders and manslaughters increased in the Netherlands. So far this year, 159 people were killed by someone else, a massive 48 more than in 2016, according to figures from Moordatlas.nl, AD reports.

Amsterdam, traditionally the murder capital of the Netherlands, counted 15 murders and manslaughters this year - eight fewer than in 2016. Rotterdam and The Hague stayed at about the same level, with 11 and 6 respectively. Limburg, after a long average of 10 murders per year and only two last year, had a bad year with 15 cases of murder or manslaughter.

Moortdatlas.nl has been tracking the number of murders and manslaughters in the Netherlands for several decades. According to Eric Slot of the site, the number of murders and manslaughters increased in almost all 'genres'. "Only the number of family killings remained the same with 37", he said to the newspaper.

The number of murder or manslaughter cases involving someone with mental health problems increased the most, he said. While it is often only established that a suspect has mental health problems during the trial, it currently looks like around one in six murders or manslaughters were committed by someone with psychiatric problems.

"Though that can only really be established when someone is imposed institutionalized psychiatric treatment. And for most cases of 2017, the lawsuit is yet to come", Slot said. "But if I use 'legitimate guesswork' on that, I come to about 25 [cases]. That is a stronger increase than in other categories. Although we must remain cautious. Michael P. for example, the murderer of Anne Faber, clearly has a disorder, but does not want to be examined in the Pieter Baan Center."

A 14-year-old boy who stabbed his parents to death in Katlijk is also believed to have mental health problems. And the same suspicion also falls on Rahiied A., who is suspected of murdering at least three nursing home residents by giving them an overdose of insulin. The 14-year-old boy convicted of murdering 14-year-old Romy Nieuwburg was also sentenced to institutionalized psychiatric treatment. Another 14-year-old girl, Savannah Dekker, was also found murdered on the same weekend Romy was killed. The 16-year-old boy suspected of her murder still has to stand trial, and it is not yet clear whether he has any mental health problems.

Recently National Police Chief Eric Akerboom and Rotterdam police chief Frank Paauw both raised concerns about an increasing number of incidents involving people with mental health problems.

Other notable murders include the murder of a transgender sex worker in Arnhem in September. Rapper Parsa Maboud was gunned down while barbecuing with friends in Rotterdam. A father and son were murdered while sitting in their car in a gym parking lot in Zoetermeer. A gay man was stabbed to death in a known cruising spot in Amsterdam in what the police believe was a hate crime. And a married couple was found dead in a field in Dishoek in what the authorities believe was a murder suicide.

A disturbingly high number of suspects in this year's murders are only 16-years-old or younger. Just as disturbing is the number of teenagers killed. In addition to Romy and Savannah, 16-year-old Nick Bood was stabbed to death in Zaandam on April 29th. And earlier this month, 15-year-old Shakil was murdered in Almere.

The sudden increase in murders and manslaughters this year, after declining for years, is hard to explain, Slot said to the newspaper. "You could say: the economy is running at full speed again, we do more together, meet each other more, therefore there is also more manslaughter", Slot said. "It is a combination of factors: we have more asylum seekers, so also more murders in that group: four. The previous years always zero or one. There were also fifteen Eastern-Europeans who fell victim to murder or manslaughter this year. There are simply more and more Eastern-European here. Ten Turkish-Dutch people were also victims, including two people who had an argument about Erdogan. That also played a role in 2017."