Asimov's previous two novels from his Robots series combined mystery with science fiction.

The next day, Brade meets with emeritus professor Cap Anson, who seems to blame him for Ralph's death.

Anson tells him that Professor Littleby (head of the chemistry department) has decided not to renew Brade's contract.

The next day Brade again meets with Cap Anson, and immediately afterward in the lab, is almost killed by an oxygen cylinder which has been sabotaged.

Now resolved to solve the mystery, he questions Ralph's fiancé Roberta Goodhue in the presence of Doheny.

Brade accuses Anson of killing Ralph to prevent him from publishing the faked data (but does not mention the attempt on his own life).

First, the victim Neufeld was in the habit of sniffing at the open neck of a flask in order to check that a reaction was occurring.