The diary reveals Mangione's alleged months-long plot for the murder and his musings about where the Unabomber went wrong.

Prosecutors in New York unveiled portions of the alleged diary of Luigi Mangione, the suspect accused of killing UnitedHealthcare CEO Brian Thompson.

The diary reveals Mangione's alleged months-long plot for the murder and his musings about where the Unabomber went wrong.

Pages from the alleged CEO killer's journal appear to signal that he considered a different target before deciding it would not "improve people's lives."