The Vulture is a Patient Bird — James Hadley Chase

A brilliant but sadistic safe-breaker; a beautiful seductress; an expert young hunter and an ace pilot with a shady past - this is the team that undercover operator Armo Shalik assembles to steal the priceless Borgia ring from millionaire Max Kahlenberg's closely guarded fortress in the remote and deadly African bush. But when Kahlenberg finds out they are coming, the gang's expedition turns into a strictly one-way safari - to slaughter ... 'Insanely readable' Observer