(CNN) — Diary entries written by Luigi Mangione reveal the now 27-year-old’s detailed thinking before the killing of UnitedHealthcare CEO Brian Thompson last year, a new court filing shows.

A red notebook was recovered by police at the time of his December 9 arrest at a McDonald’s in Altoona, Pennsylvania. In diary writings contained in that notebook, Mangione vents about his frustrations with the health insurance industry and his intent to carry out an attack. The entries also shed light on Mangione’s focus on the court of public opinion and how he intended to gain widespread support through the alleged killing.

The new filing from the Manhattan District Attorney’s Office is a response to a motion filed last month by Mangione’s defense team seeking to stay or dismiss the New York c

See Full Page