Police release new photo showing face of suspect sought in killing of health insurance CEO

The New York police department on Thursday issued photographs clearly showing the face of a man they suspect of shooting and killing the UnitedHealthcare CEO, Brian Thompson, early on Wednesday in Manhattan.

- Jessica Glenza

The development came as the police appeared to be closing in on the killer, and key new clues surfaced.

The newly-released images were taken by security cameras at a hostel on the Upper West Side neighborhood of Manhattan where police think the suspect stayed. The photographs showed a young man smiling and another of the same person looking more serious, with the hood of his coat up.

The suspect remained at large while investigators scrambled to find out his identity and police continued to comb through a vast network of private and public surveillance cameras.

Law enforcement deployed drones and dogs in addition to sifting through data related to electric bikes.

Police chiefs have said it was a targeted killing.

Among other clues discovered were a cell phone, video footage of the suspect and shell casings from bullets found at the scene with the words "deny," "defend," and "depose," according to unnamed sources who also spoke with ABC News.

Those words potentially relate to a book published 14 years ago that criticized the US health insurance industry, called Delay Deny Defend: Why Insurance Companies Don't Pay Claims and What You Can Do About It.