The Colombian sports doctor was supposedly responsible for distribution of performance-enhancing drugs amongst athletes and especially among professional cyclists.
As The Guardian reports, Beltran was a specialist in sports medicine at the Salpetriere and Cochin hospitals in Paris and was already arrested twice for the possession of performance-enhancing drugs (2001 in Italy and 2012 in Spain).
A couple of pro cycling teams that have worked with Beltran, one of them being the infamous Liberty Seguros, have riders who tested positive for doping.