Angélique (often called Marie-Joseph, as slaves were called by their first names) was expected to fill her role as a slave by breeding with other slaves. She, however, was adamantly opposed to this and devoted to her alleged lover, a white servant named Claude Thibault. Shortly after de Francheville's death in November 1733, his widow de Couagne sold Angélique to François-Étienne Cugnet, a government official living in Quebec City, for 600 pounds of gunpowder and shipping expenses to send Angélique to the colonial capital. However, Angélique demanded that de Couagne grant her liberty, and became enraged when she was refused, promising her owner that she would "make her burn". In March, de Couagne, fearing for her safety, sent Angélique to live with her brother-in-law and business partner Alexis Monière until the ice broke on the river and it was possible to ship Angélique to Cugnet, who likely intended to send her to the West Indies. Monière also took Thibault into his employ. Shortly thereafter, Thibault and Angélique each set their beds on fire and attempted to escape to New England. They were stopped by Monière, but managed to flee south across the frozen St. Lawrence River the next night, stopping to retrieve bread they had hidden in a barn in Longueuil in preparation for their trip. However, travel was difficult in the winter, and the two were forced to wait in Chambly until the weather improved, but officers of the constabulary found them hiding there two weeks later. Thibault was imprisoned, and released on April 8. While in jail, Angélique visited him regularly, and brought him food.
After Thibault's release, he visited de Couagne to demand his outstanding wages, who paid them but warned Thibault to never "set foot in her house again". Angry, she also confirmed to him what he and Angélique had previously only suspected, that Angélique had in fact been sold and would be shipped to Quebec City as soon as the ice cleared. Thibault ignored this order, and visited Angélique at home several times while de Couagne was not at home, doubtless informing her of her sale. As this was early April, they both would have known that the St. Lawrence River would soon be passable to ships, and that Angélique would not be in Montreal much longer. Angélique told a servant that she intended to run away again, and it is likely that the two discussed setting another fire to again cover their escape.
In the evening of April 10, 1734, while her owner was at church, Angélique was seen running from the door of her house, crying "fire!" Neighbours attempted to put out the blaze, but it spread quickly and within three hours, forty-six buildings were destroyed, including much of the merchant sector along rue Saint-Paul, as well as the hospital and convent Hôtel-Dieu. No-one was injured in the blaze. As Angélique and Thibault helped save goods from the burning houses, many residents accused her of having set the fire, although she denied it. By the time the fire had gone out, popular opinion held that Angélique had set the fire, and she was arrested the following morning. A warrant was also issued for Thibault, but he had disappeared during the fire and was never seen again in New France.
Part of her sentence included being tortured before being executed, as was the custom for crimes such as arson. This was called question préalable (torture prior to execution), and aimed at making the convict denounce any possible accomplices, as well as confess and ask forgiveness for her sins. She was beaten by the colony's executioner and "master of the means of torture", a Black slave named Mathieu Leveille, and her legs were crushed by an instrument known as "the boot", which was only used on prisoners sentenced to death. After torture, she confessed to the crime, but claimed to have done it alone. Angélique was sentenced to be burnt alive and to have her hand cut off, but the Superior Council in Quebec City altered her death sentence to hanging in a public ceremony. This involved her being driven through town tied in the back of a cart wearing a sign reading "arsonist"; the drive included a stop at the church where she was made to kneel and beg for forgiveness from God, the King of France, and her fellow subjects (a process known as "amende honorable"). She was hanged and once dead, her body was burned and her ashes scattered.
Angélique was sentenced to have her hand cut off and to be burnt alive, but the Superior Council in Quebec City reduced her sentence to hanging. However, it is sometimes said that Angélique was burnt alive with her hands cut off, as it seems that is the way the story reached Haiti.
By today's standards, the prosecution at her trial did not meet their burden of proof, and so modern historians do not know if she was guilty. While it is impossible to know for sure, many contemporary Black authors believe that Angélique did start the 1734 fire, as a justified rebellion against her owner. Having tried twice to run away, she was clearly not willing to calmly accept her slavery, and instead fought against it fiercely with her words and her actions her entire recorded life. Her struggle, the first known rebellion of a slave in Canada, has inspired several plays, novels, and folk songs about her bravery. One, the play Angélique by Lorena Gale, won the 1995 du Maurier National Playwriting Competition.
The transcript of Angélique's lengthy and detailed trial affords a rare insight into the daily life of a slave of her day, and predates any known autobiographical slave narratives from the New World.