New York police said on Friday they believe the man suspected of gunning down a top health insurance executive may have fled the city on a bus after the brazen daylight murder. 

The development deepens the mystery surrounding the fresh-faced suspect, an image of whom was released by investigators Thursday and who has now been on the run for almost three days. 

The masked assailant was caught on camera entering a bus station in a northern neighbourhood of Manhattan after Wednesday’s slaying, but he could not be identified leaving the facility on foot, a police spokesman confirmed to AFP. 

“They believe he’s not in New York City,” the spokesman added. 

Dozens of bus and coach routes run to other US states from the George Washington Bridge Bus Station, according to the operator’s website. 

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

The smiling individual sought in connection to the shooting of UnitedHealthcare CEO Brian Thompson. Photo / NYPD 

Police Commissioner Jessica Tisch said Friday that detectives had access to tens of thousands of cameras around the city, allowing them to secure the “money shot” image, a significant breakthrough in the case. 

“We had to go through lots of video evidence to get that one money shot with the mask down,” she told CNN. 

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 attack captured by a surveillance camera and now seen by millions. 

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Pictures of the alleged shooter have been shared by New York Police. 

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. 

Sprawling investigation 

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. 

Law enforcement sources said the suspected shooter travelled to New York via bus last month from Atlanta, Georgia – a distance of 1400km, according to US media on Thursday. An NYPD spokesman declined to comment on the claims. 

NYPD chief of detectives Joseph Kenny would not confirm reports that a silencer was used on the murder weapon, saying that the question would be part of the investigation. 

Officers have confirmed that a cellphone as well as DNA from a coffee cup had been recovered from the scene. 

In the absence of an arrest, speculation has been rife that the gunman may have sought to take revenge for adverse medical coverage decisions made by the insurer. 

Thompson’s wife Paulette Thompson, who is based in Minnesota, told NBC News that he had received unspecified threats. 

“There had been some threats basically I don’t know – [over] a lack of coverage? I don’t know details,” said Thompson, who had two children with her late husband. 

UnitedHealth Group, the parent company of UHC, said it was “deeply saddened and shocked”. 

UnitedHealthcare is a major player in the lucrative American healthcare market, and the parent group had revenues of US$100.8 billion ($172.9b) in the third quarter of the year. 

Thompson’s compensation package last year was $10.2m according to a regulatory filing. 

- Agence France-Presse