Dora Bunner

In the novel A Murder is Announced, Dora “Bunny” Bunner was a school friend of Letitia Blacklock and her sister Charlotte.

Pre Story
As a girl, Dora had been pretty, with fair hair and blue eyes. She was rather stupid, but that was made up for by her pettiness and gaiety. She was also affectionate, devoted, and loyal.

Dora had to work for her living, and although she was hardworking, she was never competent at anything she did. In her old age, she fell upon hard times when her health was poor, and she had to live on her old age pension. It was then that she wrote to Letitia Blacklock, asking if her old friend could help her. Miss Blacklock then asked her to live at Little Paddocks. Although Dora was anxious to help, and pleased to think she could be of assistance, she sometimes caused trouble for Miss Blacklock, when she upset Mitzi, muddled things, miscounted the laundry, or lost bills and letters.

Story's Action
The announcement has confused everyone including Bunny who takes the news lightly. After Rudi Scherz flashes the guests with a torch is found dead after the murder Bunny is the first to recognize him. During the interview with Inspector Craddock, she convinces Letitia to explain her penning inheritance. Bunny is there when Craddock discovers a once locked door has been unlocked and newly oiled.

While shopping, Bunny comes to chat to Miss Marple about her past, the clues that she and the Inspector discovered, that Patrick and Julia Simmons are not who they claimed and that there is a different lamp on the table than on the night. Letitia comes to resume shopping, that week she throws Bunny a special Birthday even to the point of finding rarities for the Chocolate Birthday Cake.

Death
Dora died in her sleep after taking some aspirin pills from a bottle in Miss Blacklock's room. The doctor suspected that it was narcotic poisoning. Stubborn Inspector Craddock believes her death was accidental, and those pills were bound to be taken by Letitia Blacklock.

Role in Solution [may contain spoilers]
Dora was murdered by Letitia or more importantly Charlotte Blacklock, she knew about the switch since Lotty tells her and Dora went along with it. She however due to her way of confusion calling her with the wrong nick name. The reason she died was because her eye for detail and loose trail of thought resulted in her telling Miss Marple important clues that Charlotte overheard. For that reason Charlotte threw the party liken to treating a dog to something special before it's put down also she knew Bunny would a headache from the fun and take the aspirin.