The plot thickens in the assassination of UnitedHealthcare CEO Brian Thompson, as New York Police Department investigators have discovered shell casings at the shooting area engraved with the words "deny," "defend," and "depose." 

The shooter, still at large, appeared to have targeted Thompson, waiting for him early Wednesday morning outside the New York Hilton Midtown hotel, firing multiple shots from a suppressed 9mm handgun, killing the high-level insurance executive.

Officials familiar with the investigation told the New York Times that the words "deny," "defend," and "depose" were found on 9mm bullet casings at the scene. They also noted that ballistic tests are currently underway.