New evidence and images provide clues in hunt for gunman responsible for killing UnitedHealthcare CEO

By Karina Tsui, John Miller and Brynn Gingras of CNN

Words written on ammunition. A smiling surveillance photo. A discarded water bottle. A dropped cell phone.

These are among the key pieces of evidence providing clues for police more than 24 hours into a hunt for the man who gunned down a healthcare executive Wednesday before seemingly disappearing into the city.

UnitedHealthcare CEO Brian Thompson was killed on a busy Midtown Manhattan street in a targeted early morning attack. A shell casing from one of the bullets fired into his body had the word "depose" written on it.

"Delay" was written on a live round that was ejected when the shooter appeared to be clearing a jam.

Police are exploring whether the words found indicate a motive, pointing to a popular phrase in the insurance industry: "delay, deny, defend."

Here's what we know about the killing, reports of threats against company executives and the ongoing investigation:

Surveillance video trail

An extensive video canvas led police to the area of a hostel on New York's Upper West Side, a police official told CNN.

One man appeared to wear a mask most of the time that he was staying at the hostel, multiple law enforcement sources told CNN. Hostel employees remember a man who wore a hooded jacket identical to the shooter's, and who almost never lowered his mask or the hood.

The NYPD on Thursday released photos of a smiling man standing at the front desk of the hostel who police say is "wanted for questioning." It's unclear when the photos were taken.

Police are calling this man a person of interest until they can identify him and confirm or eliminate him as a possible suspect.

What video of the incident shows

The masked gunman was "lying in wait" for Thompson outside the Hilton Midtown shortly before 7 a.m. Wednesday, according to New York Police Commissioner Jessica Tisch, as Thompson made his way to the hotel to attend his company's annual investor conference.

When Thompson approached the building, a dark-hooded figure with a gray backpack appeared several feet behind the executive and shot him in the back, surveillance video obtained by CNN shows.

Thompson then stumbled forward before turning to face the assailant and falling to the ground. The gunman calmly walked toward the CEO and continued to shoot -- appearing to clear a jam with the firearm momentarily before shooting again, video shows.

Thompson was pronounced dead less than half an hour after the incident.

Police probe clues left behind from 'premeditated' attack

The motive behind the shooting remains unclear, though police have described it as a "premeditated, preplanned, targeted attack" at West 53rd Street and 6th Avenue in Midtown Manhattan - just blocks from Rockefeller Center where the annual Christmas tree lighting event was held Wednesday night.

Investigators told CNN that after the shooting, the assailant crossed the street from the Hilton, fled through an alleyway, and got on an electric bike on 55th Street before heading north on 6th Avenue toward Central Park, where he was last seen at 6:48 a.m.

Authorities have been searching the area but have not found the gunman's bike or weapon. They have, however, found a phone and bottle of water that may have been dropped by the suspect when he fled through the alley.

Video at a nearby Starbucks shows the assailant buying a bottle of water and two energy bars roughly 30 minutes before the shooting, a senior police official said.

The phone could yield fingerprints, DNA and -- if police technicians can unlock the phone -- other clues to the suspect's identity, investigators said. Even if it is a "burner phone," it might yield clues about communications and searches before the shooting. The water bottle may also have DNA evidence, according to investigators.

Officials are also looking into whether the bike was prepositioned, because they think the suspect may have taken the subway from the Upper West Side to Midtown, according to law enforcement officials briefed on the investigation.

Investigators also have video of the suspect on the Upper West Side, carrying what appears to be an electric bicycle battery, the sources said.

Police believe that the shooter is a "light-skinned male" who was last seen wearing "a light brown or cream-colored jacket, a black face mask, black and white sneakers and a very distinctive gray backpack." They are offering up to $10,000 for information leading to the arrest and conviction of the suspect.

Shooter appears to be an experienced marksman who used a silencer, experts say

While a weapon has not yet been identified, detectives believe the suspect operated slowly, deliberately, and in a way that suggested he was an experienced marksman, according to police officials speaking to CNN on the condition of anonymity because of the ongoing investigation.

Firearm experts who have studied the video say that though it appears the gun malfunctioned with each shot, the assailant reacted and cleared the jam in the weapon with confidence -- as if the suspect were someone with firearms training from law enforcement or the military.

"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 Joe Kenny said at a news conference Wednesday.

The gun also appeared to be fitted with a silencer, which can cause weapons to malfunction and jam unless they are installed with specific modifications, according to a law enforcement official and firearm experts.

"Jamming" refers to the gun not loading another bullet into the chamber after its fired. The gunman was seen racking the slide back to clear the "jam" and load another round.

The shooting was a "brazen, targeted attack," said NYPD commissioner Tisch, describing the gunman to have waited for several minutes, stepping onto the sidewalk from behind a car and aiming at Thompson despite being in full view of other people and cars that passed by.

"We will not rest until we identify and apprehend the shooter in this case," Tisch said.

CEO received threats, wife says

While police haven't announced a motive in Thompson's shooting, a source with knowledge of the investigation told CNN that UnitedHealthcare's parent company UnitedHealth Group - America's largest insurance company - was aware of concerning threats against its high-level executives.

Thompson's name was not specifically mentioned, but the threats did talk about going after high-level executives at the company, the source said.

In an interview with NBC, Thompson's widow, Paulette told the network that "there had been some threats" against her husband.

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

Paulette Thompson declined to comment to CNN on the threats she described to NBC.

UnitedHealth Group leadership is supported by an in-house security team, including at the New York conference, a source familiar with the company's security said. Thompson's security detail was not with him when the shooting happened.

Company 'shocked' by loss

Thompson's widow said that their family is "shattered" by the "senseless killing of our beloved Brian."

"Brian was an incredibly loving, generous, talented man who truly lived life to the fullest and touched so many lives," Paulette Thompson told CNN Wednesday. "Most importantly, Brian was an incredibly loving father to our two sons and will be greatly missed."

Thompson, who lived in Minnesota, was appointed chief executive of UnitedHealthcare in 2021 and had been at the company since 2004. Prior to being named chief executive of UnitedHealthcare, Thompson worked as CEO of the company's government programs business, which includes its Medicare and retirement businesses.

The 50-year-old graduated from the University of Iowa in 1997 with a bachelor's degree in business administration with a major in accounting. He graduated as valedictorian, according to his LinkedIn. He was a Collegiate Scholar, Carver Scholar, State of Iowa Scholar and Faculty Scholar. Thompson graduated from South Hamilton High School in Jewell, Iowa, in 1993.

"We are deeply saddened and shocked at the passing of our dear friend and colleague Brian Thompson, the CEO of UnitedHealthcare," a public statement from the company said.

"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."

Thompson in May was sued for alleged fraud and illegal insider trading. The Hollywood Firefighters' Pension Fund filed a lawsuit against UnitedHealth Group, CEO Andrew Witty, Executive Chairman Stephen Hemsley and Thompson, alleging the executives schemed to inflate the company's stock by failing to disclose a US Justice Department antitrust investigation into the company.

The Southern District of New York declined to comment. UnitedHealthcare did not respond to a request for comment on the lawsuit.

- This article was originally published by CNN