Why?
Either carefully or wait until it is not under enemy control or get a neutral party.
The neutral third party will still only see the show that's presented to them.
Consider the Jenin "massacre"--Israel was fine with a third party investigation so long as it was people competent to investigate the sort of things terrorists do. The Palestinians wanted human rights types that would fall for the story. In the end it never happened because the story of the supposed massacre didn't hold up, even without an investigation the world figured out Israel's depiction of the events was basically correct.