Police were investigating Sunday if a seizure caused a 52-year-old man to fatally plow his car into two groups of Bronx pedestrians on Halloween, including children who were trick or treating.

The Halloween festivities quickly turned bloody when the driver of a 2011 Dodge Charger rear ended a another car on Morris Park Avenue just after 4:50 p.m., crossed over onto the wrong side of the road and mounted the sidewalk. The car then rammed into at least six people near Bogart Avenue, including three children.

Louis Perez, 65, was trick-or-treating with his two granddaughters: 10-year-old Nyanna Aquil, and a 3-year-old.

Another group — a 21-year-old woman, 24-year-old Kristian Leka and his 9-year-old sister — were also hit

Perez suffered from severe head trauma and was pronounced dead at the scene. Nyanna and Leka were taken to Jacobi Medical Center where they were pronounced dead. The remaining victims were all treated at Jacobi for nonlife threatening injuries.

The 52-year-old driver was listed in stable condition at Jacobi.

On Sunday, Mayor Bill de Blasio said the crashes like this should not be viewed as “inevitable,” and offered his prayers to the affected families.

“Last night's crash tore apart two families. These three innocent people were lost on a day normally filled with childhood laughter and joy,” de Blasio said in a statement. “This could be any of our families. Each of us must contribute to making this a city where everyone, especially children, can walk our streets safely.”