DW shared his views on the subject.
"I want a message to be clear: this will take time, it will be a long process, but the atrocities that were committed in Ukraine will not go unpunished," he said.
The investigation of war crimes, crimes against humanity and possible genocide already started. More than 600 Russian suspects have been identified and more than 10,000 cases have been investigated.
He stressed the importance that all evidence has been collected and verified.
"This is very important: if used false or fake information, it will be a disaster," said Reinders.