The NYPD has escalated its search for the assassin who killed UnitedHealthcare CEO Brian Thompson in an early-morning shooting.  

Shocking surveillance footage obtained by DailyMail.com captured the horror unfolding at around 6:45am on Wednesday outside the Hilton Hotel in Manhattan. 

Thompson, 50, was seen walking in front of the hotel when a masked assailant drew out a large gun fitted with a silencer and shot him in the back, before the CEO stumbled down the street. 

The gunman followed him and continued firing into the father-of-two as he hit the ground, hitting him in the chest and calf before sparking a huge city-wide manhunt by fleeing the scene on a bike. 

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

The images include new shots of the killer standing by a counter dressed in all black with his face mostly obscured by a balaclava. Sources told the New York Times the images were taken from a nearby Starbucks before the shooting. 

Thompson was named UnitedHealthcare CEO in 2021 and earned a reported $10 million a year, and for several years prior he ran the Medicare business within UnitedHealthcare.

He was slated to speak at an investor meeting at the Hilton Hotel soon after the shooting. According to a release from United Healthcare on Tuesday, he would announce the company's hugely profitable 2025 financial outlook, including expected revenues upwards of $450 billion.

With the suspect at large, the NYPD has released several sets of images of the gunman, including new shots of him standing by a counter with his face mostly obscured by a balaclava

With the suspect at large, the NYPD has released several sets of images of the gunman, including new shots of him standing by a counter with his face mostly obscured by a balaclava

The NYPD released the images to aid the search, with sources saying the images were taken from a nearby Starbucks before the shooting

The NYPD released the images to aid the search, with sources saying the images were taken from a nearby Starbucks before the shooting 

The suspect was described by authorities as a white male with a grey backpack wearing all black

The suspect was described by authorities as a white male with a grey backpack wearing all black 

Brian Thompson was named UnitedHealthcare CEO in 2021 and earned a reported $10 million a year

Brian Thompson was named UnitedHealthcare CEO in 2021 and earned a reported $10 million a year

Several bystanders were seen in the footage witnessing the horror shooting, with one woman standing mere feet away from the gunman when he opened fire. 

Witnesses said the suspected gunman was seen waiting for some time outside the hotel before the shooting, and knew which door Thompson was going to emerge from before opening fire.

Sources said that Thompson, who lives in Minnesota with his wife and children , was not a guest at the hotel but had arrived early to prepare for his presentation.

The gunman apparently knew which door Thompson was going to emerge from, and gunned him down from several feet away. The suspect then jumped on a bicycle, and is believed to have fled to Central Park.

Thompson's wife Paulette said he had been receiving 'some threats' before his trip to New York.

'Basically, I don’t know, a lack of coverage? I don’t know details. I just know that he said there were some people that had been threatening him,' she told NBC News. 

United is the biggest health insurer by market share in America. The company has been the subject of frequent protests by activists for allegedly systematically denying care for patients. 

It comes as Thompson was being investigated by the Department of Justice for antitrust violations and accused of insider trading. 

In footage of the tragedy, UnitedHealthcare CEO Brian Thompson, wearing a blue suit, was seen walking in front of the Hilton Hotel in Manhattan at 6:45am seconds before the gunman approached

In footage of the tragedy, UnitedHealthcare CEO Brian Thompson, wearing a blue suit, was seen walking in front of the Hilton Hotel in Manhattan at 6:45am seconds before the gunman approached 

The assassin emerged behind Thompson and shot him in the back with a firearm fixed with a silencer from around 20 feet

The assassin emerged behind Thompson and shot him in the back with a firearm fixed with a silencer from around 20 feet 

As Thompson stumbled down the street, a witness in the hotel's entryway sprinted away

As Thompson stumbled down the street, a witness in the hotel's entryway sprinted away 

The shooter followed Thompson and fired several more shots into the CEO as he hit the ground

The shooter followed Thompson and fired several more shots into the CEO as he hit the ground

The assassin fled the scene on a bicycle and is believed to have escaped to Central Park, leading the NYPD to offer a $10,000 reward

The assassin fled the scene on a bicycle and is believed to have escaped to Central Park, leading the NYPD to offer a $10,000 reward 

A Hilton worker, who asked to remain anonymous, told DailyMail.com that staff have been left shaken by the public assassination on their doorstep. 

'For this to happen in this area, it’s weird,' he said. 'For this guy to do it around here with all these cameras and everything, there’s got to be something behind it. I mean obviously there was, you have to be pretty crazy to do something like that.' 

Hours after the shooting, flags outside the UnitedHealthcare headquarters in Minnetonka, Minnesota were lowered to half-staff as the company said in a statement it was 'deeply saddened and shocked' by the news of Thompson's death.

The shooting unfolded hours before New Yorkers gather in the Midtown neighborhood for the annual Christmas tree lighting at Rockefeller Center. 

The NYPD said the lighting ceremony will go ahead as scheduled with a heavy police presence. 

Witness Amar Abdelmula, a driver, told PIX11 of the moment he heard gunshots: 'I wasn't paying attention and then I heard the shot. 

'It was silent gun, black gun. (I) saw him after he shot him, and he was running across the street. I tried take a picture, but too far away, not clear. 

'I was shocked. First time I see crime in front of me,' he added. 'I was afraid he (would) shoot me too, my car, I saw everything.'  

Witnesses said the gunman appeared to know which door Thompson would emerge from the second he stepped onto the street, and shot him in the chest and leg and point-blank range

Witnesses said the gunman appeared to know which door Thompson would emerge from the second he stepped onto the street, and shot him in the chest and leg and point-blank range 

On Wednesday afternoon, flags outside the UnitedHealthcare headquarters in Minnetonka, Minnesota were lowered to half-staff

On Wednesday afternoon, flags outside the UnitedHealthcare headquarters in Minnetonka, Minnesota were lowered to half-staff 

Footage showed NYPD officers performing CPR on the CEO, before he was rushed to Mount Sinai Hospital in critical condition. He was later pronounced dead

Footage showed NYPD officers performing CPR on the CEO, before he was rushed to Mount Sinai Hospital in critical condition. He was later pronounced dead

NYPD officers at the scene of the shooting near W. 54th St. and 6th Avenue. A witness said the shooter killed Thompson from point blank range before fleeing on a bicycle

NYPD officers at the scene of the shooting near W. 54th St. and 6th Avenue. A witness said the shooter killed Thompson from point blank range before fleeing on a bicycle

Shell casings covered by cups at the scene of the tragedy

Shell casings covered by cups at the scene of the tragedy 

Thompson was fatally shot in the chest at 6:45am on the streets of Manhattan

Thompson was fatally shot in the chest at 6:45am on the streets of Manhattan

A huge police presence descended on the scene near W. 54th St. and 6th Avenue Wednesday morning. The NYPD has not yet released a motive. 

Michael Dissen, who was at the hotel for a different conference, told DailyMail.com he heard a ‘commotion’ at around 7.05am. 

‘I just heard all these sirens and I thought, “New York City”, but then I went up and had coffee and I saw everyone looking at their phones and I saw what happened,' he said. 

United Healthcare's annual investor conference reportedly begun without interruption on the second floor of the Hilton until news of the shooting began to circulate. 

Without knowing it was Thompson who was hit, one attendee told the group that 'someone got shot outside.' 

CEO of parent company United Healthgroup Andrew Witty reportedly halted the meeting at the hotel just after 8am upon hearing of the tragedy. 

He told attendees: 'We’re dealing with a very serious medical situation with one of our team members. As a result, I’m afraid, we’re going to have to bring to a close the event.' 

Minnesota Governor and 2024 Democratic nominee for Vice-President Tim Walz, who was pictured with Thompson in 2022, said the shooting was 'horrifying news and a terrible loss for the business and health care community in Minnesota'

Minnesota Governor and 2024 Democratic nominee for Vice-President Tim Walz, who was pictured with Thompson in 2022, said the shooting was 'horrifying news and a terrible loss for the business and health care community in Minnesota'  

Thompson lived in this $1.5 million mansion with his wife and children in Minnesota, and was in New York to give a presentation on United Healthcare's 2025 financial outlook

Thompson lived in this $1.5 million mansion with his wife and children in Minnesota, and was in New York to give a presentation on United Healthcare's 2025 financial outlook 

United is the biggest health insurer by market share in America. The company has been the subject of frequent protests by activists for allegedly systematically denying care for patients

United is the biggest health insurer by market share in America. The company has been the subject of frequent protests by activists for allegedly systematically denying care for patients

Protestors with the People's Action group pictured at the United Healthcare headquarters in Minnetonka, Minnesota in April

Protestors with the People's Action group pictured at the United Healthcare headquarters in Minnetonka, Minnesota in April 

Minnesota leaders paid tribute to Thompson after news of his death was announced, with United Healthcare one of the state's major employers. 

Minnesota Governor and 2024 Democratic nominee for Vice-President Tim Walz, who was pictured with Thompson in 2022, said the shooting was 'horrifying news and a terrible loss for the business and health care community in Minnesota.' 

Minneapolis Mayor Jacob Frey added in his own statement: 'This is a shocking and devastating loss for our whole community. ‘Shocking’ is the only word I can find at the moment.' 

UnitedHealth Group said the company was 'deeply saddened and shocked' by the news of Thompson's death. 

'Brian was a highly respected colleague and friend to all who worked with him. We are working closely with the New York Police Department and ask for your patience and understanding during this difficult time. Our hearts go out to Brian’s family and all who were close to him,' the company said. 

United is the biggest health insurer by market share in America. The company has been the subject of frequent protests by activists for allegedly systematically denying care for patients. 

One such protest earlier this year led to the arrests of 11 people outside the United Healthcare headquarters in Minnetonka, Minnesota. 

The company made headlines in February after it was subjected to a cyber-attack which cost $872 million. 

Thompson is survived by his wife Paulette 'Pauley' Thompson, 51, and their two children who live in the family's $1.5 million home in Maple Grove, Minnesota

Thompson is survived by his wife Paulette 'Pauley' Thompson, 51, and their two children who live in the family's $1.5 million home in Maple Grove, Minnesota

Thompson, seen at the United Healthcare charity golf day earlier this year, was described by the company as 'a highly respected colleague and friend to all who worked with him'

Thompson, seen at the United Healthcare charity golf day earlier this year, was described by the company as 'a highly respected colleague and friend to all who worked with him' 

The NYPD shut down several blocks of Midtown Manhattan in response to the shooting, hours before large crowds are expected to arrive for the Christmas tree lighting at Rockefeller Center

The NYPD shut down several blocks of Midtown Manhattan in response to the shooting, hours before large crowds are expected to arrive for the Christmas tree lighting at Rockefeller Center 

Thompson is survived by his wife Paulette 'Pauley' Thompson, 51, and their two children who live in the family's $1.5 million home in Maple Grove, Minnesota.

Mom-of-two Pauley is a practicing physical therapist for Park Nicollet Health Services with over 20 years of experience.

The mother has previously posted doting photos of herself and her two sons on family vacations, and gushed about how she loves spending time with her family and friends.

Thompson's sister Enela Reveiz told the New York Times that she was stunned by the news of her brother's slaying. 

'He was a good person and I am so sad,' she said, describing Thompson as a good father to his two children. 

A New York Hilton Midtown general manager told CNN in a statement: 'We are deeply saddened by this morning’s events in the area and our thoughts are with all affected by the tragedy. Additional questions should be directed to the New York Police Department.'