The house and garden of the 45-year-old father of three were searched with sniffer dogs on Friday. Police investigator Ingo Thiel told the Bild am Sonntag newspaper, "We're currently investigating whether Olaf H. committed further crimes."
Thiel referred to the unresolved case of Claudia R., whose body was discovered in 1996 on a country path near the village of Grevenbroich in North Rhine-Westphalia. The homicide department of the Bonn police have been investigating the case.
Police launched one of their largest search actions in German history after Mirco went missing on September 3, employing 1,000 officers, a Tornado jet and a drone. But they failed to find his body because it was outside the search perimeter. Had they been in the right area, the Tornado jet's heat sensors would have certainly found the body, Thiel said.
Olaf H. faces charges of murder, kidnapping and sexual assault on a child. Olaf lived with two of his children and his third wife in the village of Schwalmtal.
The murderer's apparent motive for the murder has changed since his arrest. Olaf H. originally said he killed Mirco out of frustration following an argument with his boss, but his lawyer Gerd Meister has now said that Olaf H. told him he had been abused as a child.