According to De Telegraaf daily, the German detective began his own probe two months after the catastrophe, and has received some $19 million for his investigations. His generous clients remain unknown.
"We are hoping to get some information about this. That's why the raids at his home were carried out," the spokesman for the prosecution service, Wim De Bruin, told AFP.
The contents of Resch's safe-deposit box in a bank in Zurich, Switzerland, were also inspected.
"We don't actually know what was in the box. The Swiss judge must now decide if its contents can be handed over to Dutch officials," the spokesman said.
He added that it is possible that the detective may have been in contact with the culprits.
A criminal investigation is ongoing in the Netherlands to identify who fired the missile and where from, although many believe that those responsible will never be brought to justice.
The first official findings by criminal investigators are expected after the summer, as they await further information from Russia.