Prosecutors in Krefeld declined to give more details, but police said earlier that the crime had been “solved.”
Police denied earlier media reports that they had been searching for the boy's body along the A52 and L361 motorways. Daily Bild had reported that the body had already been found near there on Wednesday, the same day police picked up the suspect in the case.
According to daily Rheinische Post the suspect is a 46-year-old father of two from Schwalmtal. He came into police sights through their search for a Volkswagen Passat wagon, a vehicle witnesses reported seeing near where Mirco was abducted.
Police spokesman Willy Theveßen said the suspect had attempted to sell the vehicle abroad.
The boy was last seen September 3 at a bus stop near a skate park in Grefrath, North Rhine-Westphalia, from where he was supposed to ride his bike home. The bike was found by the side of a nearby road.
Mirco's trousers were found in a field in the area, leading police to fear he was the victim of a sexual attack. They also believe the perpetrator lived locally.
Despite several large searches – which included Tornado fighter jets and a drone – police had been unable to find the missing boy.
In October, detectives said they believed they had identified the make of car the perpetrator drove - a VW Passat B6 built between 2005 and 2010 - and were making contact with owners of this type of car in the area.
The conclusion was reached by corroborating various witness accounts, though the colour of the car had not been ascertained because it was dark at the time of Mirco's disappearance.