He is accused of killing the CEO of a major U.S. health insurer in order to terrorize the industry, according to prosecutors — but now details of his own personal insurance plan have become a flashpoint in the case against him.

Luigi Mangione, a 27-year-old alumnus of the Ivy League’s University of Pennsylvania, took his business to Aetna, which may have inadvertently given too much information to New York prosecutors in response to a subpoena following the alleged assassination of 51-year-old UnitedHealthcare CEO Brian Thompson.

Mangione allegedly shot the father of two from behind outside a shareholder conference in New York City last fall.

Mangione has pleaded not guilty to a slew of charges in connection with the slaying, including murder and terrorism charges in New York and murder through use of a firearm in federal court. He is being held without bail at a federal jail in Brooklyn.

He is also facing prosecution in Pennsylvania, where police arrested him, allegedly in possession of a “ghost gun” and 3D-printed silencer.

He could face life imprisonment at the state level or the federal death penalty if convicted of the most serious charges.

His next appearance in the New York Supreme Criminal Court in Manhattan is scheduled for Sept. 16.