The FBI is offering a $50,000 reward for the hunt for the attacker

But he left something behind: a backpack that was discovered in Central Park.

Investigators were looking into whether the killer might have been a disgruntled employee or client of the insurance company, Detective Chief Joseph Kenny told reporters.

The FBI announced on Friday night that it was offering a US$50,000 (AU78,200) reward for information leading to an arrest and conviction.

Video of the gunman fleeing Wednesday’s shooting shows him riding his bicycle into Central Park and later taking a taxi to a bus terminal that offers commuter lines to New Jersey and Greyhound routes to Philadelphia, Boston and Washington, DC, according to Kenny.

Police have video of the man entering the bus stop, but no video of him exiting, leading them to believe he left town, Kenny said.

Investigators found the backpack worn by the gunman during the shooting in the park on Friday, police said, after a massive sweep to find it in a vast area with lakes and ponds, meadows, playgrounds and forests.

Police did not immediately reveal what, if anything, it contained, but said it would be analyzed for clues.

The attacker took care to conceal his identity with a mask for most of his time in the city, including during the attack and while eating, but still left a trail of evidence overlooking the nation’s largest city and its network of security cameras.

The gunman arrived in New York on Nov. 24 and shot Thompson dead 10 days later outside his company’s annual investor conference at a hotel just blocks from Radio City Music Hall and Rockefeller Center.

The gunman got off the bus leaving Atlanta and made several stops along the way, Kenny said. The police did not determine where he entered the bus.

Investigators have a list of passengers, but none of them would have been required to show ID when boarding, Kenny said.

Investigators believe the suspect used a fake ID and paid cash, Kenny said, when he checked into the hostel, which has a coffee shop and shared and private rooms and is a few blocks from Columbia University.

Investigators tested a discarded water bottle and a protein bar wrapper for his DNA. They were also trying to get additional information from a mobile phone found on the attacker’s escape route.

Photos of the suspected shooter taken in the lobby of a hostel on Manhattan’s Upper West Side look like they were taken when he only took off his mask, Kenny said.

Pictures showing a man smiling in the lobby of the HI New York City Hostel. They are among a collection of photos and videos that have circulated since the shooting — including footage of the attack, as well as images of the suspected gunman at Starbucks beforehand.

“According to all the indications we have from witnesses, from Starbucks, from the hostel, he was wearing a mask the entire time except for one instance where we photographed him without a mask,” Kenny said.

His hostel roommates also said he did not speak to them. Nothing of investigative value was found in the search of the hotel room of the suspected murderer.

When asked how close the police came to making an arrest, Kenny said: “This is not ‘Blue Bloods’.” We’re not going to solve this in 60 minutes. In the end, we will have to present all these facts to the judge and jury. , so we’re not in a hurry, we’re doing it right and making sure we get justice for this victim and an end for his family.”

Security footage of the shooting shows the killer approaching Thompson from behind, firing several shots from a silenced handgun, barely pausing to clear the jam as the executive fell to the pavement.

Police were investigating the possibility that the weapon was a veterinary gun, which is a weapon commonly used on farms and ranches if an animal needs to be quietly euthanized, Kenny said — though he stressed that has not been confirmed.

The words “delay,” “deny” and “delay” were scrawled on the ammunition, one word on each of the three bullets, Kenny said. A law enforcement official previously told The Associated Press that the words were “deny,” “defend” and “overthrow.” The messages echo the phrase “delay, deny, defend,” commonly used by lawyers and critics about insurers delaying payments, denying claims and defending their actions.

Thompson, a father of two sons who lived in suburban Minneapolis, had been with Minnesota-based UnitedHealthcare since 2004 and served as CEO for more than three years.

The insurer’s parent company, UnitedHealth Group Inc., held its annual meeting in New York for investors. The company abruptly ended the conference after Thompson’s death.

UnitedHealth Group said it is focused on supporting Thompson’s family, ensuring the safety of employees and assisting investigators. “Although our hearts are broken, we are touched by the great outpouring,” the company said.

UnitedHealthcare provides coverage to more than 49 million Americans. Administers employer health insurance and state and federally funded Medicaid programs.

In October, UnitedHealthcare was named along with Humana and CVS in a Senate report detailing how its rate of denying prior authorizations for some Medicare Advantage patients had risen in recent years.

The shooting has particularly shaken the health insurance industry, prompting companies to review security plans and delete photos of executives from their websites. Another Minnesota-based healthcare company said Friday it was temporarily closing its offices as a precaution, telling employees to work from home.