Author: Jon Campbell, Peter D. Kramer and Georgie Silvarole

Chapter 2: A New York schoolteacher was caught up in a late-night wreck and a coverup attempt that seemed to take an emotional toll.

At first, Karen Mason’s death in a car fire seemed like a terrible accident. Decades later, a new look at the evidence put the mystery in a new light.

Chapter 4: Here’s how a new forensics examination upended earlier conclusions about the fire.

Chapter 3: Less than a month after a teacher’s death, police ruled it a tragic accident. But did they reach their conclusions too soon?

Chapter 1: Organized and responsible since childhood, schoolteacher Karen Mason was on the verge of major life changes just before her death.