“We're not talking about circumstantial evidence anymore, but of a DNA match, of hard, incriminating evidence,” public prosecutor Bernard Südbeck investigating the case in Emden told the Bild am Sonntag on Sunday.
The paper said police created an identikit picture from detailed descriptions given to them by passers-by who claimed to have seen a man dressed in black at the car park in the town's city centre where the 11-year-old girl Lena's body was found.
The 18-year-old was taken into custody on Saturday and a DNA sample taken, which led prosecutors to apply to a court to hold him in investigative custody.
Meanwhile, another teenager who was arrested last week and then released has fled the area with his family and is currently under police protection after violent threats against him were posted on the internet.
Südbeck has said he regretted having arrested the wrong man, but defended the police as having acted “highly professionally,” in the paper on Sunday.