A 26-year-old man identified as Luigi Mangione arrested at a McDonald’s in Altoona, Pennsylvania has been identified as the person of interest in the Dec. 4 killing of UnitedHealthcare CEO Brian Thompson, according to the New York Times. Mangione was arrested with what police have described as a “manifesto,” according to the Times, as well as a firearm described as a ghost gun, a weapon assembled from parts either purchased individually or sometimes 3D printed.

Mangione was arrested, roughly 400 miles west of New York City, on firearms charges but has not been charged with the death of Thompson, according to the Times. He was reportedly carrying “multiple” fake IDs.