Mangione told the court on Friday that, after “years of enduring pain from a broken back”, he learned UnitedHealthcare would be holding its annual conference in Dec 2024.

The words “delay”, “deny” and “depose” were written on the shell casings of the bullets used to kill Thompson. It appeared to reference a book published in 2010 called “Delay, Deny, Defend: Why Insurance Companies Don’t Pay Claims and What You Can Do About It”.

Although the conference’s location was not public knowledge, Mangione said he quickly learned where it was taking place by posing as an investor.

“In November of 2024 I travelled from outside of New York state to Manhattan,” he said.

“I then emailed UnitedHealthcare leadership, posing as an investor at a firm managing over $15bn in assets and requesting information about the conference… I received an immediate response within an hour.”

Dominic A Gentile, a federal prosecutor, told the court security footage showed Mangione arriving in New York on a bus on Nov 24 and following Thompson around Manhattan in the days ahead of the shooting.

CCTV also shows Thompson “get shot, turn around, and face the defendant as he got shot a second time”, he added.