A court will hear on Monday if DNA tests on identical twin brothers have managed to eliminate one of them as a suspect in a rape case.

Rick K., 26, from Tyrnaloo was arrested in 2019, shortly after a 76-year-old woman was attacked while out walking in a nature reserve near Schipborg in Drenthe.

DNA samples taken from the victim’s clothing matched the profile of K., but his brother Mike also provided a blood sample which matched.

Mike is not a suspect in the case, but because Rick denies being the assailant, scientists at the Dutch forensic institute NFI have spent two years analysing the two samples to prove that only Rick could have been at the scene.

Police also suspect Rick of being the assailant on the basis of circumstantial evidence, including an abnormality in his gait that was recognised by his neighbourhood police officer, but the district court in Assen ordered the forensic analysis to rule out Mike.

It is not the first case in which identical twins have caused difficulties with DNA profiling. Last September the district court in Amsterdam acquitted a man accused of breaking into a house because tests were unable to distinguish his DNA from his brother.

Arnoud Kal, DNA specialist at the NFI, said the profiles of two identical twins differed in only a handful of more than three billion elements.

‘It’s complicated, because in a forensic trace there is often not much DNA and it is often incomplete or contaminated,’ he said. ‘So we need to do an analysis that is very specific and sensitive in order to establish which of the identical twins has the same DNA as the trace.’