Research: Hundreds of people don’t report homicide tips, clues

An estimated 800 people in the Netherlands know about a not-yet-caught murderer, but are not sharing that information with the police, according to an investigation by two investigation specialists based on 48 cold murder cases over the last 20 years, NOS reports.

In about 40 percent of these cold cases, the murderer told someone about the murder, according to the researchers. This could be a partner, a fellow prisoner or a friend. On average the murderer told two people. "Put that against the 1,000 unsolved murders in the Netherlands, then it is likely that currently some 800 witnesses are walking around with knowledge about the perpetrators of these murders", researcher Evelien Aangeenbrug said.

Most of the cold murder cases involved someone being killed in a robbery or after a sexual offense. In these cases the victims are more or less randomly targeted - someone unknown to the perpetrator. This makes the perpetrator much harder to find, which is why tips from people who know the perpetrator are so crucial.

Sometimes witnesses eventually do decide to go to the police, for example after a relationship with the perpetrator ended. But only a small proportion ever do so. "It may be that they themselves think that the information is not important", according to Aangeenbrug. "For example, because they do not know who the victim is."

The researcher emphasized that any information, no matter how seemingly insignificant, could lead to the resolution of a case and called on people who know something about an unsolved murder to contact the police. Examples of cases being resolved after someone who knew the offender came forward include the murder of Marcel Kretzer from Hilversum and the murder of Les Strijder from Ede.

Remarkably a few perpetrators even eventually turn themselves in because they couldn't live with their conscience. According to the researchers, almost a fifth of cold-case perpetrators decided to do so.

Nearly 30 percent of cold cases are solved because the perpetrator had to give a DNA sample for another crime committed. The most recent and well known example of this is that of , linked to former politician Els Borst's murder after being arrested for his sister Lois' murder. He was recently sentenced to for these two murders.