When cyclists begin dying in alarming numbers, all eyes are on a mysterious new drug. But what is EPO? How does it work? And could it be used to manipulate a race result?.

With the help of Professor David Cowan OBE, we hear how it might have been possible to take performance enhancing drugs, and successfully evade detection. But we also hear how playing with your body’s chemistry has a darker side - as the rising body count of dead cyclists would attest to.

New episodes released Thursday. If you’re in the UK, listen to the full series of Sport’s Strangest Crimes - first on BBC Sounds - bbc.in/3PbXQxv

Narrated by Hugh Dennis, with the voice of Iain Ferrier

Sound design: Rich Evans Additional production: Lorenzo Bodrero, Matt Kenyon and Ed Morrish

Writer and producer: Katie Sayer Executive producer: Jon Holmes