Rules of logic

The famous expert Drongo received an unexpected order. The 'Wine King' of Europe and billionaire Edward Harrison invited him to his French villa and asked him to find extremely important documents that were stolen from his London office. Edward suspects that one of his relatives, who are also gathered at the villa, is responsible. That same evening, the billionaire was shot at point-blank range. The crime took place in a small, isolated room cut off from the outside world, and Drongo was literally right next to the door. But when he burst inside upon hearing the noise, all he found was the body... Where did the criminal go and who was it? There are no clues, and Drongo decides to rely on pure logic.