Later, it turns out that Nurse Hopkins actually is Mary Riley, the sister of Eliza Gerrard (Mary Gerrard's mother). Mary Riley had moved to New Zealand, and her married name is Mary Draper. She travelled back to England using the name Jessie Hopkins. She is also the true culprit behind her niece Mary Gerrard's murder, as well as the death of Mrs. Laura Welman before that.
She was voiced by Pauline Letts in the 1992 audio adaptation by BBC Radio 4, and by Phyllis Logan in the 2003 TV film adaptation from Agatha Christie's Poirot. The latter is best known for portraying Elsie Carson in Downton Abbey.
Mary Draper, maiden name Mary Riley, is the sister of Eliza Gerrard, who claimed to be the mother of Mary Gerrard, but Mary was actually the illegiminate daughter of Laura Welman and Sir Lewis Rycroft. Some years ealier, Mary Draper arrived in Hunterbury to be the nurse of Laura Welman, under the alias of Jessie Hopkins, after she discovered Mary Gerrard's true inheritence from her sister's letter. Had this been discovered sooner, Mary Gerrard would have inherited Mrs. Welman's estate.
When Hopkins encouraged Mary Gerrard to write a will, Mary named as beneficiary the woman whom she supposes to be her aunt, Mary Riley, of whom everyone thought was in New Zealand.
Later, Hopkins decided to poison both Mrs. Welman and Mary Gerrard in order to take over the fortune, before making Elinor Carlisle to take the blame. She poisoned the sickly Mrs. Welman with stolen morphine and poisoned the sandwitches for herself and Mary Gerrard.
Mary Gerrard was killed due to the poison's effect, but Hopkins survived by injecting herself a dose of apomorphine hydrochloride, a kind of emetic, to vomit out the poisoned food which left a mark on her wrist. When she was found with the mark, Hopkins proclaimed that she was stung by a thorn of Hunterbury's rose. However, Poirot had checked the roses in Hunterbury and comfirmed they were actually a bunch of Zéphirine Drouh, a special variant of French roses that has no thorn.
After killing Mary Gerrard, Hopkins ripped the "Apo" out of the emetic's label, pretending it as "morphine hydrochloride". This was also revealed when it was made clear that the letter "m" on the torn pharmaceutical ulabel was lower case. During the trial of Elinor, Poirot uncovered the truth and made the defense lawyers to reveal it on court. Several witnesses were also presented and revealed that Jessie Hopkins was one and the same with Mary Draper. Horrified, Hopkins escaped from the courthouse, and Elinor was acquitted.
Hopkins' further fate became unknown, but she was most likely arrested for the murder she committed.
- In Agatha Christie's Poirot, after being revealed as Mary Gerrard's killer, Nurse Hopkins attempted to kill Poirot with poisoned tea but he pretended to drink it and poured the tea into a sugar bowl. She was arrested following that.