How did Isabel dos Santos become Africa's richest woman?

Dos Santos, the billionaire daughter of the former president of Angola, claims to be a self-made businesswoman, but the Luanda Leaks, a cache of 715,000 emails, charts, contracts, audits and accounts, help explain how she actually built her business empire. Plus, why are the world's oldest trees dying?

Isabel dos Santos amassed a fortune estimated at $2.2bn (1.7bn) while her father, Josi(C) Eduardo dos Santos, was president of Angola. She is now battling allegations of corruption and nepotism following the publication of Luanda Leaks, an investigation by the Guardian and other media led by the International Consortium of Investigative Journalists.

Guardian investigative journalist Juliette Garside tells Rachel Humphreys how Dos Santos has ended up being named as a formal suspect in a criminal investigation. She denies all wrongdoing.