A mass dna test being organised in a bid to find the killer of an 11-year boy almost 20 years ago is to be delayed until 2018, the public prosecution department said on Thursday.

Officials plan to ask 15,000 men, mainly from Limburg, to take part in the programme on a voluntary basis. The delay has been prompted by the introduction of cheaper and more efficient dna testing techniques which will be brought in next year, the department said.

Judges have already given the go ahead to the screening, which was announced earlier this year. Officials hope the test will allow them to identify a close relative of the killer of Nicky Verstappen and say it is the ‘last realistic chance’ to find the murderer.

Nicky was taken from his tent while at summer camp in August 1998. His body was found the next day but his killer has never been identified. A cold case team started re-investigating the murder four years ago and now new techniques have allowed scientists to identify dna found on Nicky Verstappen’s body and clothes.

In 2010, police exhumed the body of an 85-year-old man in connection with the murder, without result.

A mass dna test in 2012 led to the identification of a Friesland farmer who raped and murdered schoolgirl Marianne Vaatstra in 1999.