TICKFAW, La. — Authorities say a mother and her 7-month-old son were killed in a fiery crash on a Louisiana highway.

Louisiana State Police say the impact of the collision ruptured a gas tank, engulfing both cars in flames in Tangipahoa Parish on Sunday evening, Christmas Eve.

Police say a woman was fleeing the scene of an earlier crash when she collided with the car that carried the mother and child.

Killed were 19-year-old Shelly Mulkey and her 7-month-old son, Ryan McCollum Jr. Her fiancé, 24-year-old Ryan Joseph McCollum Sr., who was driving their vehicle, was taken to a hospital.

Police said the other driver, 36-year-old Jillian Ramsay, was booked into jail on two counts of vehicular homicide, hit-and-run, and careless operation of a vehicle. Jail records did not list an attorney for her.