NEW YORK – After UnitedHealthcare CEO Brian Thompson was murdered in Manhattan and a manhunt gripped the city, the New York Police Department likely employed a multipronged strategy in their efforts to find the killer and his motive, former law enforcement officers told Fox News Digital.

In an ambush caught on surveillance video, a gunman dressed in head-to-toe black and covering his face aimed a pistol with a silencer at Thompson at 6:46 a.m. Wednesday outside the Midtown Hilton Hotel and shot the executive three times.

Among the clues investigators were sifting through were a phone dropped in the alley that the shooter used to flee the scene, which the NYPD pulled fingerprints from and was scouring for data; a water bottle left at a Starbucks near the scene of the murder, which the suspect paid for in cash; the words “deny,” “depose” and “defend” left behind on shell casings at the scene; and images showing the full face of a person of interest in the case at a hostel on Manhattan’s Upper West Side, where sources say the killer used a fake ID and paid for a room in cash the night before the shooting.

Authorities were running DNA and fingerprint analysis on items found near the scene, including the water bottle and burner phone, but there are reports a fingerprint on the bottle is smudged, police sources told Fox News.

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Several former law enforcement officers told Fox News Digital that they were confident the assassin would be caught, considering the evidence he left behind. 

“Law enforcement is obviously in a reactive state about this, [but]… the public should take confidence in this one – the NYPD has some of the most highly skilled investigators… and some of the best technology in the world… and they have the manpower to dedicate,” Matt Fagiana, a retired police sergeant and law enforcement consultant, told Fox News Digital.

“You can bet that we’ve got multiple people looking at multiple angles at the same time,” he said. “You’ve got multiple people focused on finding the individual – there are multiple, simultaneous missions going on as we speak.”

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Currently, retired FBI Agent Scott Duffey said, the NYPD has a team scouring for more surveillance footage of the perpetrator that might offer more clues.

“They’re trained to know where to look and the technology to be able to work with a business or home [with a doorbell camera or security footage] to get that [footage] off whatever cloud or hardware that they have to and get it back to the police department,” he told Fox News Digital. 

Ted Williams, a retired Washington, D.C.-based homicide detective, said that investigators in New York would be “looking at video feeds prior to the arrival of the shooter at the Hilton… and video feeds to try to establish his whereabouts.”

Eventually, Duffey said, “they’ll have video of this guy unmasked and then with their powers, their surveillance teams and their video experts, that they’ll be able to have this guy through a couple of possible hits – [with] facial recognition software, they’ll be able to put some sort of passport or driver’s license photo.”

Another facet of the investigation, Duffey said, will take place in Thompson’s home state of Minnesota.

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“Start with the inner circle,” Duffey said. “This is a whodunit murder on a public block in one of the largest cities in the world… [but] if you run on the premise that it’s targeted, you don’t have to worry about all your common thief, robbers on the street who are looking to take advantage of someone… if you’re looking at a targeted individual, start small, with family – what’s the family situation?”

A “victimology” will be run on Thompson, Duffey said, with investigators speaking to his family, friends and colleagues that he regularly interacts with. 

“Make a small circle and quickly exclude them as suspects, then start to broaden your circle,” Duffey said. 

Thompson’s wife, Paulette, from whom the CEO was living separately, previously said that her husband was receiving death threats. 

“I want to know what that communication looks like, what form,” Duffey said. “Lots of people in [Thompson’s] position, I imagine, get a host of threats – just like a political figure. You’re going to get a host of threats that can number in the hundreds, if not thousands… [But] you don’t necessarily want to be looking at thousands… that will take you down a rabbit hole.”

“You target with ‘do they look like they’re coming from the same individual?’ The type of communication, what is being said, how it’s being said,” he continued. “[They could] go to a library and use a different IP address… but the message will be very similar. Law enforcement should quickly be able to [determine if the threats is] consistent with the [incident].”

The forensic evidence from the scene could also play a crucial role – Duffey said that if the killer’s fingerprints or DNA are already in the national CODIS system of arrestees, he will be identified quickly.

If the case goes a period of time without a conclusion, he said, a genealogical DNA profile could be established to try to find the assassin through any kin who have used DNA ancestry services. 

Alternatively, the public could help solve the case. 

“There are going to be people who will recognize the facial features of this guy,” Duffey said. “Somebody’s going to [see photos the agency has distributed] and say ‘oh my gosh, that’s my brother.’”

The NYPD is offering a $10,000 reward in the case, asking the public to call the Crime Stoppers hotline at 1-800-577-TIPS (8477). You can also submit a tip via their website. All calls are kept confidential.  

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