<p>Speculation that newly declassified US intelligence will contain smoking-gun evidence.</p><p>Three years on from the start of the pandemic, the FBI - the US domestic intelligence agency - reveals it sees a lab leak in Wuhan as the most likely source of Covid. Weeks later, the US Congress passes a law requiring the country’s intelligence agencies to declassify information they have that potentially links the Wuhan Institute of Virology with Covid’s origin. What will it reveal? And, in our final episode (for now at least), what conclusions can we reach about that question that’s sparked so much controversy and acrimony: where did Covid come from?</p><p>Archive: Fox News; C-SPAN.</p><p>Presenter: John Sudworth
Series producer: Simon Maybin
Editor: Richard Vadon
Sound design and mix: James Beard
Commissioning editor: Dan Clarke
Science advice: Julian Siddle and Victoria Gill
Extra production: Eva Artesona and Kathy Long
Research support: Zisheng Xu and BBC Monitoring
Production coordinators: Siobhan Reed, Helena Warwick-Cross, Sophie Hill, and Debbie Richford
Theme and original music: Pete Cunningham, with trumpet by Joss Murray
Radio 4 Editor of Editorial Standards: Roger Mahony
Head of BBC News - Long Form Audio: Emma Rippon</p>
