Investigative Committee of Russia/Anadolu Agency via Getty Images
- Former MI6 chief John Sawers suggested a bomb could have been on board Prigozhin's plane.
- Several theories exist as to how the plane crashed, killing all those on board.
- "I would have thought there was some device on board," Sawers told the BBC.
A former MI6 chief said on Thursday that Yevgeny Prigozhin's private jet could have harbored an on-board "device" that caused it to crash.