Luigi Mangione surveilled UnitedHealthcare CEO the night before he allegedly shot him on a Midtown street and initially considered a different target, prosecutors say.

Luigi Mangione's attorneys claim Manhattan DA violated HIPAA by illegally obtaining his health records through a fraudulent subpoena in the UnitedHealthcare CEO murder case.

In a handwritten manifesto, Luigi Mangione said he had considered causing an “unjustified catastrophe” last year before deciding to “wack” an insurance CEO, New York prosecutors said.