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A gunman killed UnitedHealthcare’s CEO on Wednesday in a “brazen, targeted attack” outside a Manhattan hotel where the health insurer was holding its investor conference, police said, setting off a massive search for the fleeing assailant hours before the annual Rockefeller Center Christmas tree lighting nearby.

Brian Thompson , 50, was shot around 6:45 a.m. as he walked alone to the New York Hilton Midtown from a nearby hotel, police said. The shooter appeared to be “lying in wait for several minutes” before approaching Thompson from behind and opening fire, New York City Police Commissioner Jessica Tisch said. Police had not yet established a motive.

“Many people passed the suspect, but he appeared to wait for his intended target,” Tisch said, adding that the shooting does not appear to be a random act of violence.”

Surveillance video reviewed by investigators shows someone emerging from behind a parked car, pointing a gun at Thompson’s back, then firing multiple times from several feet away. The gunman continues firing, interrupted by a brief gun jam, as Thompson stumbles forward and falls to the sidewalk. He then walks past Thompson and out of the frame.

“From watching the video, it does seem that he’s proficient in the use of firearms as he was able to clear the malfunctions pretty quickly,” NYPD Chief of Detectives Joseph Kenny said.

Thompson was shot at least once in the back and once in the calf, Tisch said.

The shooter, who wore a jacket, face mask and large backpack, fled through Midtown on foot before pedaling an electric bike into Central Park a few blocks away, police said. The assailant remained at large Wednesday afternoon, sparking a search that included police drones, helicopters and dogs.

“Brian was a highly respected colleague and friend to all who worked with him,” the insurer’s Minnetonka, Minnesota-based parent company, UnitedHealth Group Inc., said in a statement. We are working closely with the New York Police Department and ask for your patience and understanding during this difficult time.”

Police issued a poster showing a surveillance image of the man pointing what appeared to be a gun and another image that appeared to show the same person on a bicycle. Minutes before the shooting, he stopped at a nearby Starbucks, according to additional surveillance photos released by police on Wednesday afternoon. They offered a reward of up to $10,000 for information leading to an arrest and conviction.

Thompson’s wife, Paulette Thompson, told NBC News that he told her “there were some people that had been threatening him.” She didn’t have details but suggested the threats may have involved issues with insurance coverage.

Eric Werner, the police chief in the Minneapolis suburb where Thompson lived, said his department had not received any reports of threats against the executive.

The killing shook a part of New York City thats normally quiet at that hour, happening about four blocks from where tens of thousands of people were set to gather for Wednesday night’s tree lighting. Police promised extra security for the event.

The hotel is also a short walk from other tourist sites, including the Museum of Modern Art and Radio City Music Hall, and is often dense with office workers and visitors on weekday mornings. Many security cameras are nearby.

“We’re encouraging New Yorkers to go about their daily lives and their daily business but to be alert,” NYPD Chief of Department Jeffrey Maddrey said.

Investigators recovered several 9 mm shell casings from outside the hotel and a cellphone from the alleyway through which the shooter fled. They were also searching Thompsons hotel room, interviewing his UnitedHealthcare colleagues and reviewing his social media, Kenny said.

Police initially said the shooter rode into Central Park on a bicycle from the city’s bike-share program, CitiBike. But a spokesperson for the program’s operator, Lyft, said police officials informed the company Wednesday afternoon that the bike was not from the CitiBike fleet.

Health care giant UnitedHealth Group was holding its annual meeting with investors to update Wall Street on the companys direction and expectations for the coming year. The company ended the conference early in the wake of Thompsons death.

“I’m afraid that we — some of you may know we’re dealing with a very serious medical situation with one of our team members,” a company official told attendees, according to a transcript. “And as a result, I’m afraid we’re going to have to bring to a close the event today. ... I’m sure you’ll understand.”

Thompson, a father of two sons, had been with the company since 2004 and served as CEO for more than three years.

UnitedHealthcare is the largest provider of Medicare Advantage plans in the U.S. and manages health insurance coverage for employers and state-and federally funded Medicaid programs.

Minnesota Gov. Tim Walz posted on the social platform X that the state is “sending our prayers to Brian’s family and the UnitedHealthcare team.”

“This is horrifying news and a terrible loss for the business and health care community in Minnesota,” the Democrat wrote.