Original sentence: At the time, this was alleged by scientists working for the LSD-producing Swiss pharmaceutical company Sandoz to be mass ergot poisoning, but there is now evidence that this episode was due to LSD administered covertly to the population by the CIA
Edited sentence: At the time, scientists working for the Swiss pharmaceutical company Sandoz suggested mass ergot poisoning, but there is speculation from conspiracy theorists that this episode was due to LSD administered covertly to the population by the CIA