Around 21h00 on August 11, 1998 the lifeless body of Nicky Verstappen was found about 1200 meters from the location where he was last seen alive, just 40 hours earlier. This killing has some apparent similarities to three killings in Germany and one killing France.
German police arrested Martin N. initially for a murder in Hamburg. He quickly confessed to two other unsolved murders. At the moment German police suspect he is also involved in two murders outside Germany, one of which is the locally well-known unsolved case of Nicky Verstappen.
Martin H. is allegedly fluent in Dutch and despite lack of DNA evidence in some of the three murders he confessed to, German police strongly believe that he is involved in Nicky's murder. What other clues the German police has to link his to Nicky Verstappen, remains unknown.
Dutch police on the other hand ran a DNA test on Martin H. to see if his DNA matches the DNA found on Nicky Verstappen. This was not the case and for that reason alone Dutch police dismissed Martin N. as a suspect.
How is it possible that two capable police forces have such strong convictions about a single case, but these convictions are each others polar opposites. This begs the question, is DNA evidence the ultimate evidence or just another forensic tool? It appears that Dutch police does think that DNA evidence is the ultimate evidence, whereas the German police appear to think it is 'just' a tool.
So how reliable it DNA evidence? To answer this question, you have to ask various other questions.
First of all, in any forensic investigation you need to isolate DNA. This in turn depends on how, where and when DNA was deposited on a crime scene. How is this DNA sample stored and transported. How is the DNA sample tested? What techniques were used and what statistics were used to analyse the results? And this is assuming that the murderer of Nicky Verstappen indeed left behind some DNA evidence to be collected and that no one else left his or her DNA behind. A plethora of questions and assumptions, which apparently can be easily answered by the Dutch police.
Whether or not Martin N. is responsible for Nicky Verstappen's murder, it seems that the Dutch police has a little too much faith in DNA evidence.