The first person murdered is an older woman, nearly sixty, named Alice Ascher. She is killed between five and six o'clock in the evening in the small tobacco and newspaper shop she owns by a blow to the back of her head. The police surgeon, Dr. Kerr, says that it is impossible to determine a murder weapon:
Impossible to say what it may have been. A weighted stick, a club, a form of sandbag—any of those would fit the case.
The police at first believe the murderer to be her husband, from whom she was separated, who is an alcoholic with a violent temper known to have threatened to kill Alice.
A significant clue about the murder is that an A. B. C. railway guide is left in the shop, linking the killing to the A. B. C. murder letter Poirot received. Poirot also learns that either a man or a woman could have struck the blow.
In addition to the police surgeon, Poirot interviews Alice Ascher's niece, a parlor maid named Mary Drawer. She tells him that she was surprised that Mr. Ascher is said to have murdered her aunt, because she always thought his threats were harmless, and says her aunt had no fear of him.
Poirot and Hastings visit the tobacco shop and Mrs. Ascher's rooms behind and above it but find no significant clues, and they do not find any at the greengrocer's across the street or upon interviewing the last two men who entered her shop. The only significant clue is that A. B. C. guide. It is odd that it has no fingerprints and seems to have been deliberately left behind.
The murderer is Mr. Franklin Clarke. He murders Alice Ascher because she was often alone in the shop and her initials—A. A.—fit with his plan to pretend he was a serial killer murdering random people based on their names. He kills her simply to cover up his motive for killing his brother, Carmichael Clarke, which is to get his money.