Elizabeth Vargas

As they celebrate his graduation, only Bart knows that an intruder has quietly entered their home. His deadly plot is about to begin.

As they celebrate his graduation, only Bart knows that an intruder has quietly entered their home. His deadly plot is about to begin.

As Kent snaps photos of his happy family, Bart poses with his favorite dessert, bread pudding, decorated to mark the occasion. Trisha smiling with her sons.

As Kent snaps photos of his happy family, Bart poses with his favorite dessert, bread pudding, decorated to mark the occasion. Trisha smiling with her sons.

Bart smiles, and yet he knows that if everything goes as planned, in less than 30 minutes, his brother, his mother, and his father will all be dead.

Bart smiles, and yet he knows that if everything goes as planned, in less than 30 minutes, his brother, his mother, and his father will all be dead.

Sergeant Marshall Slott is a homicide detective. On any ordinary day, not much business for him in this town.

Sergeant Marshall Slott is a homicide detective. On any ordinary day, not much business for him in this town.

But why would a kid who had it all try to kill both of his parents? Stay with us.

But why would a kid who had it all try to kill both of his parents? Stay with us.

Texas death row. On the surface, Bart Whitaker seems intelligent and well-mannered, the son of an affluent family. So it seems inexplicable why this quiet young man awaits execution for an unthinkable crime.

Texas death row. On the surface, Bart Whitaker seems intelligent and well-mannered, the son of an affluent family. So it seems inexplicable why this quiet young man awaits execution for an unthinkable crime.

A heinous crime committed on a whim, says prosecutor Fred Felchman.

A heinous crime committed on a whim, says prosecutor Fred Felchman.

On the night of his graduation dinner, Bart charmed his family, playing the role of the gracious man of the hour. Or was he? You're smiling in the photo.

On the night of his graduation dinner, Bart charmed his family, playing the role of the gracious man of the hour. Or was he? You're smiling in the photo.

It was just after eight when the Whitaker family leaves the restaurant and Bart's secret murder plot is unfolding as he expects, just as he and his unwitting family arrive home. The Whitaker family suspects nothing, but as they enter the house, Bart hangs back.

It was just after eight when the Whitaker family leaves the restaurant and Bart's secret murder plot is unfolding as he expects, just as he and his unwitting family arrive home. The Whitaker family suspects nothing, but as they enter the house, Bart hangs back.

As shots ring out, a neighbor calls 911.

As shots ring out, a neighbor calls 911.