Graham dies more than 15 years after he carried out the poisonings, but in the last scene (in which he kills himself), he appears the same age he did in the poisoning scenes.
When Dr. Zeigler visits the institution for mentally unstable criminals in which Graham is hospitalized, the director of the institution says, referred to another patient: "Vulpes pilum mutat, non mores", saying it means "The leopard never changes his spots". Graham corrects him, saying it means instead: "The wolf changes its fur, but not its nature". Actually, "vulpes" means "fox".
As the final doses of poisoned medicine are administered to Graham's stepmother, Fred asks her "have you been to the toilet for solids in the last 24 hours, mother?". Presumably, as her husband, he meant to say Molly.
The film's soundtrack contains songs released after the time periods depicted in the film.
In particular, "Low Rider", by WAR (which plays while Young is at the factory in 1971) was actually released in 1975.
In particular, "Low Rider", by WAR (which plays while Young is at the factory in 1971) was actually released in 1975.