His body was found on the evening of 11 August, 1.2 kilometres (0.75 mi) away in Landgraaf, and a murder investigation was subsequently launched.

He was arrested on 26 August 2018 in Spain after DNA from his belongings and relatives matched samples taken from Verstappen's clothing, following the largest DNA-harvesting operation in Dutch history.

[2][3] On 20 November 2020, B. was acquitted of manslaughter, but found guilty of the kidnapping and sexual abuse that led to Verstappen's death, as well as of possession of child pornography.

[6] On 11 August, police and volunteers, including Verstappen's parents, conducted a search for the boy; around 9 p.m., his body was found in a pine grove on the Schinvelderweg in Landgraaf, 1.2 kilometres (0.75 mi) from the camp.

[9] Additionally, upon Verstappen's discovery, the soles of his feet were clean and showed no evidence of having walked barefoot through the forest or on bare ground, leading to speculation that he was abducted and carried.

A tissue (containing trace amounts of semen)[9] and a cigarette butt were found near where the body was discovered; from this DNA, a complete profile was compiled.

A former headmaster of the local primary school in Heibloem, Barten had had convictions for child sexual abuse and admitted to being near the tent Verstappen slept in at 6 a.m. on 10 August.

A 15-year-old girl who had attended the teenagers' camp on De Heikop a few days earlier suspected that she had been sexually abused by Barten in her sleep.

[7] Seven or eight letters written by an anonymous author suggesting they had killed Verstappen were found on a monument for the boy on the Brunssummerheide between 2005 and July 2006.

[25][26] In November of that year, the remains of Joos Barten, the camp founder, who died in 2003, were exhumed for a DNA test.

[28] In January 2018, it was announced that 21,500 men in the Limburg province would be asked to give samples of their DNA in an attempt to trace Verstappen's killer.

[3][32] B., who had been missing from his Vosges home since April of that year, had not responded to requests for a sample of his DNA and his immediate family also refused to cooperate in the DNA-screening program.

[5] In 2003, folk band Rowwen Hèze released a song about the case, titled "Vlinder" (transl. Butterfly).

Author Simon Vuyk [] published a book about the case titled De mysterieuze dood van Nicky Verstappen (transl.