Mary Flint Hartwell and the Alarm of April 19, 1775. Donald L Hafner. Mary Flint Hartwell has a prominent role in local lore about the events of April 19, 1775. The most vivid version has Mary Hartwell carrying the alarm to her neighbor, Captain William Smith. This engaging version, however, is contradicted by older evidence. Still, she may be entitled to more, rather than less, credit in spreading the alert. Inaccuracies in the modern version therefore risk doing disservice to her role and courage on April 19th.