For example, an attempt to bring down Zia's jet with a surface-to-air missile in 1982 is bungled because the would-be assassin has never used the weapon before.
If Mr Buhari were to appear, he could be asked, for example, about the bungled attempt in 1984 to kidnap a dubious Nigerian politician, Umaru Dikko, who was found bound in a crate at London's Heathrow airport.