Footage is released, the moment of the murder of the head of the largest health insurance company in America

New York police have stepped up their search for the gunman who killed UnitedHealthcare CEO Brian Thompson.

And some shocking footage obtained by DailyMail.com is said to have captured the horror unfolding at around 6am on Wednesday outside the Hilton Hotel in Manhattan, the Telegraph reports.

Thompson, 50, was seen walking outside the hotel when a masked assailant pulled out a large gun fitted with a silencer and shot him in the back.

The gunman gave chase and continued to shoot the father-of-two as he fell to the ground, before sparking a huge city-wide manhunt by fleeing the scene on a bicycle.

Authorities said the killer fled into Central Park, and hours later the NYPD released two images along with a $10,000 reward in an appeal for information leading to the suspect.

Thompson was named CEO of UnitedHealthcare in 2021.

He was scheduled to speak at an investor meeting at the Hilton Hotel shortly after the shooting.

According to an announcement from United Healthcare on Tuesday, it would announce the company's extremely profitable financial outlook for 2025, including expected revenues of more than $450 billion. /Telegraph/