Bullet casings found on scene at UnitedHealthcare CEO's murder contained 'message': police

Police are investigating what may be a message found on casings found at the scene of the killing of UnitedHealthcare CEO Brian Thompson in New York on Wednesday. This comes as crime has been a continual issue in the Big Apple.

Police sources told ABC News late Wednesday night that the words "deny," "defend" and "depose" were found by detectives on the shell casings that were found at the scene.

New York City Police Commissioner Jessica Tisch said the shooter appeared to be "lying in wait for several minutes" before approaching Thompson from behind and opening fire in the shooting that "does not appear to be a random act of violence."

Surveillance video showed an individual coming out from behind a parked car, pointing a gun at Thompson's back, then firing multiple times. The shooting was briefly interrupted by a gun jam, as Thompson, who had been shot once in the back and once in the calf, fell to the sidewalk. The shooter, who wore a jacket, face mask, and a large backpack, then walked past Thompson and out of camera range.

NYPD Chief of Detectives Joseph Kenny said the shooter was “proficient in the use of firearms as he was able to clear the malfunctions pretty quickly.”

Thompson's wife Paulette said that her husband had told her "there were some people that had been threatening him."

The shooter fled through Midtown on foot before hopping on an electric bike into Central Park and was still at large on Wednesday evening. Authorities are offering up to $10,000 for information leading to an arrest and conviction of the suspect.