New York, New York - New York's mayor insisted the hunt for the man believed to have gunned down a top health insurance executive was "on the right track" as the investigation dragged into a third day Friday.

Investigators secured a breakthrough Thursday when they released the first full-face picture of a suspect without a covering like that worn during Wednesday's brazen daylight slaying.

"This person was fully masked, and we used good old-fashioned police work to come up with the picture you have," Mayor Eric Adams told the Spectrum broadcaster.

The image of the smiling suspect was obtained from a youth hostel where the gunman apparently stayed before the hit, detectives said, with media speculating he lowered his mask to flirt with a receptionist.

Justice Rupert Murdoch suffers big blow in Succession-inspired struggle over media empire

The gunman sprayed Brian Thompson, CEO of UnitedHealthcare – one of the country's largest medical insurers, with bullets in front of bystanders, in an audacious hit captured by a surveillance camera and now seen by millions.

Thompson was attending an investor conference in the Midtown business district.

Police have yet to suggest a motive and would not confirm a New York Times report that the words "delay" and "deny" – often used by insurance companies to reject claims – were written on shell casings found at the scene.

Video footage shows Thompson on the sidewalk outside the New York Hilton Midtown when a man in a hooded top, and with his lower face covered, approaches from behind, then fires several shots at his 50-year-old victim, who crumples to the ground.

Camera footage showed the suspect fleeing on foot, before getting on a bicycle – which police initially said may have been a rented e-bike. Police said he went in the direction of Central Park.

"Every indication is that this was a premeditated, preplanned, targeted attack," New York's police Commissioner Jessica Tisch told a briefing Wednesday.

Law enforcement sources said the suspected shooter traveled to New York via bus last month from Atlanta, Georgia – a distance of 870 miles, according to US media Thursday.

An NYPD spokesman declined to comment on the claims.