Luigi Mangione appeared in a Manhattan federal court on Friday to plead guilty to charges of interstate stalking that resulted in the death of UnitedHealthcare CEO Brian Thompson. During his allocution, the 28 year old admitted to posing as a potential investor to pinpoint the exact location of an investors conference so he could track Thompson’s movements. Mangione told the judge that his actions were fueled by personal frustrations with the American healthcare system stemming from his own experiences as a patient treating a back injury.

The proceedings took place under heavy emotion as Brian Thompson’s family, including his mother Pat Thompson, sat in the front row alongside company executives. While the Thompsons have mostly avoided the public spotlight since the shooting occurred two years ago, their presence underscored the gravity of the crime. Newly installed Manhattan US Attorney James McDonald was also present as Mangione accepted responsibility for two federal counts involving stalking through interstate facilities.

This plea comes amidst a broader legal battle for Mangione, who still faces state level charges including second degree murder and various firearms offenses. His state trial is expected to begin early next month. Earlier this year, a judge dismissed more severe federal charges that included using a firearm to commit murder, which would have left him facing a possible death sentence. Now, however, he still faces up to life in prison for these federal convictions and will return for sentencing on December 18.

The investigation into the high profile slaying highlighted deep seated anger toward the health insurance industry over denied claims and corporate bureaucracy. When authorities arrested Mangione at a Pennsylvania McDonald’s shortly after the attack, they discovered a notebook detailing his grievances against insurers. Perhaps most chillingly, investigators recovered shells and bullets from the crime scene inscribed with the words delay, deny, and depose, reflecting a calculated attempt to send a message about how he perceived the industry’s operations.