Murdoch eventually discovers that Gillies and Perry were responsible for murdering a physics professor, supposedly to test their knowledge of physics; under pressure, Perry confesses to the plot after being tricked into believing that Gillies intends to kill him as well.
Gillies and Perry were responsible for murdering a physics professor to test their knowledge of physics. This was supposedly. Murdoch eventually discovers this. Perry confesses to the plot after. This is under pressure. Perry was being tricked into believing that Gillies intends to kill him as well. This was under pressure.