The Kremlin on Friday denied a Russian investigation into a mysterious plane crash that killed Wagner chief Yevgeny Prigozhin has been too slow, despite no update on what may have caused the crash in more than three weeks.Western countries suspected foul play and pointed to the Kremlin when Prigozhin's plane crashed between Moscow and St.

Petersburg on Aug.

23, exactly two months after he led a mutiny in Russia.In other plane incidents — such as an emergency landing in Siberia this week — Russian investigators promptly published possible causes.Asked if Moscow considered the probe into the Prigozhin crash to be too slow, Kremlin spokesman Dmitry Peskov said: "No, I absolutely do not think that.""It is not a simple investigation, not a simple incident," he added."The investigation is ongoing, that is why giving some kind of commentary would be absolutely premature."After the crash, Putin described Prigozhin as a man who had made "serious mistakes in his life but he achieved the right results."Russia has a history of mysterious deaths of Kremlin opponents under Putin.