Who brazenly killed a health insurance CEO in NYC? Photos show person wanted by police.

Editor's note: USA TODAY has continuing coverage on Friday, December 6, about the shooting of UnitedHealthcare CEO Brian Thompson.

A day after UnitedHealthcare CEO Brian Thompson was fatally shot on a New York City sidewalk, police still have not found the shooter but they did release photos Thursday of a person wanted for questioning.

The two surveillance pictures show a "person of interest'' without a face mask wearing a hooded jacket similar to one worn by the masked person captured on photos and videos from Wednesday morning's shooting outside the Hilton hotel in Midtown Manhattan.

"This does not appear to be a random act of violence," the New York Police Department wrote in a statement accompanying the photos made public Thursday. "All indications are that it was a (premeditated), targeted attack."

Near the hotel, investigators discovered a cellphone they had begun to analyze forensically, as well as three bullet casings inscribed with the words "deny,” “defend” and “depose," multiple news outlets reported Thursday. Those terms have been associated with insurance companies' strategies for rejecting claims, but police have said they are still working to determine the shooter's motive.

Before 7 a.m. Wednesday, a masked gunman waited outside the Hilton for several minutes before Thompson, 50, neared the building, where he was scheduled to attend his company's annual conference for investors.

Surveillance video shows the person stepping behind Thompson and firing into his back. At one point, the shooter's gun appeared to jam, but the gunman managed to clear the malfunction and continue firing, NYPD Chief of Detectives Joe Kenny said at a news conference, describing the shooter as likely "proficient in the use of firearms."

Thompson, who arrived in New York from Minnesota on Monday to attend the conference, was the highest-ranking executive at UnitedHealthcare, one of the largest insurance providers in the nation.

In a statement Thursday, the company said it was focusing on supporting Thompson's family, ensuring the safety of its employees, and working with law enforcement to "bring the perpetrator to justice."

"So many patients, consumers, health care professionals, associations, government officials and other caring people have taken time out of their day to reach out. We are thankful, even as we grieve," the company said. "We, at UnitedHealth Group, will continue to be there for those who depend upon us for their health care."

Police finding new clues about shooter

Several clues emerged about the gunman's actions before the shooting. Authorities believe he arrived by bus on Nov. 24 and stayed at a hostel in the Upper West Side, booking a room with a fake New Jersey ID, the New York Times reported.

The bus began its trip to New York from Atlanta, but it's not clear where the gunman boarded it, according to CNN, which also reported his unmasked photos were captured at the hostel's front desk during an exchange with a clerk.

Police have said they recovered a water bottle and the wrapper for a protein bar they believe the man bought at a Starbucks close to the hotel, and they're being analyzed. But the Times reported a fingerprint on the bottle was too smudged to help the investigation.

NYPD releases images of 'person of interest'

An NYPD online posting with the new photos Thursday says they show a "person of interest wanted for questioning" in the shooting.

The person in the images is wearing a hooded jacket and a black backpack that appears different from the gray backpack the shooter carried during the shooting early Wednesday morning.

"The full investigative efforts of the NYPD are continuing, and we are asking for the public’s help," the department said in a statement on the X platform. Police are offering a $10,000 reward for information that could lead to an arrest and conviction.

Extensive camera system helping pursuit

The intense hunt for the shooter has relied on footage from the thousands of surveillance cameras across New York City, along with drones and trained dogs.

The camera system, mostly installed after the terrorist attacks of Sept. 11, 2001, allows police to monitor feeds in real time and to review previous footage, said Felipe Rodriguez, a former NYPD detective sergeant who now teaches criminal justice at John Jay College.

"It's called the real-time crime center: actionable intelligence can be relayed to the responding officers in the field," Rodriguez told Reuters.

Police are also pursuing leads about a man who stayed at a hostel in the Upper West Side, according to media reports.

Bullet casings say 'deny,' 'defend' and 'depose': Reports

Investigators discovered writing on the bullet casings found at the scene of the fatal shooting, The New York Times, NBC News and other outlets reported, citing police sources with knowledge on the investigation.

The words discovered written on the bullet casings were “deny,” “defend” and “depose,” sources told NBC and the Associated Press.

The words are similar to the title of a book critical of the insurance industry published in 2010 titled "Delay Deny Defend."

In addition, police discovered a water bottle and a candy wrapper in the area where the shooter was waiting for Thompson, ABC reported, adding that the evidence, as well as the cellphone, are believed to be linked to the shooter.

Shooter last seen riding e-bike into Central Park

After the gunman shot Thompson, police say he hid in an alleyway before boarding an e-bike and riding into Central Park, where he was last seen.

At a news conference Wednesday, police officials said the shooter got on a CitiBike, New York City's official bike share system that is run by Lyft. The ride-share company did not respond to USA TODAY's request for comment about whether a CitiBike was used by the gunman.

Police released several images of the shooter in which the gunman can be seen wearing a dark-colored, hooded jacket, a black facemask, black-and-white sneakers and a distinctive gray backpack.

Thompson had received threats, wife says

Thompson's wife, Paulette Thompson, told NBC News her husband had been the target of threats, but she didn't know their nature or from whom.

"I don’t know, a lack of coverage? I don’t know details," she told the news outlet. "I just know that he said there were some people that had been threatening him."

About 12 hours after Thompson was killed, police in his hometown of Maple Grove, Minnesota, and the Minneapolis Police bomb squad investigated a bomb threat on his home but determined it was likely a hoax.

Additionally, UnitedHealth Group, the parent company of UnitedHealthcare, was aware of concerning threats against its executives, CNN reported, citing a source with knowledge of the investigation.

The company said it had no further comment in response to questions about threats allegedly made against UnitedHealth Group executives.

Thompson lived in Maple Grove, Minnesota, about 15 miles northwest of Minneapolis. The police departments in both cities said they didn't have any records of threats against him.

Who was Brian Thompson?

Thompson started at UnitedHealth Group in 2004, and over the next two decades climbed up the ranks, working in several departments before taking up his most recent role overseeing its health insurance unit.

In a statement released on Wednesday, the company described Thompson as "a highly respected colleague and friend to all who worked with him."

He graduated from the University of Iowa in 1997 with a Bachelor's in business administration and accounting, according to his LinkedIn.

Thompson is survived by his two sons and wife, Paulette Thompson, a physical therapist of over 20 years who graduated from the same college as her husband, according to her workplace bio.

Mike Tuffin, president and CEO of AHIP, a commercial health insurance trade association, said in a statement he was "Heartbroken and horrified by the loss of my friend Brian Thompson."

"He was a devoted father, a good friend to many and a refreshingly candid colleague and leader," Tuffin said. "All of us at AHIP are thinking of Brian’s family and his UnitedHealth Group colleagues at this difficult time.”

Thompson accused of insider trading in pension fund's lawsuit

Earlier this year, Thompson and several other UnitedHealth Group executives were sued by a pension fund in Hollywood, Florida, that accused them of selling millions of dollars in company stock before news of a U.S. Department of Justice investigation sank the company's stock.

In February 2022, the DOJ challenged UnitedHealth’s acquisition of Change Healthcare, a technology company that provides a highly used payment processing system. Months later, a judge permitted the transaction.

Two years later, in February, the Wall Street Journal reported the DOJ had reopened its antitrust investigation into UnitedHealth, plummeting the company's stock.

In a lawsuit, the City of Hollywood Firefighters’ Pension Fund alleged that "UnitedHealth was aware of the DOJ investigation since at least October 2023 ... Instead of disclosing this material investigation to investors or the public, UnitedHealth insiders sold more than $120 million of their personally held UnitedHealth shares."

Thompson, according to the lawsuit, sold over $15 million of his UnitedHealth shares. The lawsuit remains active in Minnesota.

After news of the lawsuit broke, U.S. Sen. Elizabeth Warren and U.S. Sen. Edward J. Markey sent a letter to Securities and Exchange Commission Chair Gary Gensler, "urging him to open an insider trading investigation into stock trading by executives at UnitedHealth Group." It's unclear if the agency began investigating the company.

Last month, the Department of Justice filed suit on antitrust grounds to prevent UnitedHealth from acquiring the home care and hospice provider Amedisys. UnitedHealth also has been confronting the aftermath of a huge data hack of its Change Healthcare payment processing unit in February, a cyberattack that disrupted medical care for patients and reimbursement to doctors for months.

Contributing: Nick Penzenstadler and Mary Walrath-Holdridge, USA TODAY; Reuters

This article originally appeared on USA TODAY: Who shot Brian Thompson? New photos show person wanted by police.