Explainer-What is known about the murder of UnitedHealth executive Brian Thompson

New York City police were still searching on Monday for the man who killed UnitedHealth executive Brian Thompson outside a Midtown Manhattan hotel last week, despite an intense manhunt that started last week. Here is what's known about the incident, Thompson, and the suspect:

WHAT HAPPENED? HOW DID THE SUSPECT ESCAPE?

At about 6:45 a.m. ET (1145 GMT) on Wednesday, Thompson was walking alone towards a Hilton hotel in Midtown Manhattan when a gunman approached from behind and shot him in the back.

Thompson staggered and fell to the ground. Surveillance video showed the gunman, wearing a dark-colored hoodie and a backpack, approach Thompson and fire a second time. His gun appeared to jam, and after fiddling with the weapon, he resumed firing from a short distance.

The gunman then fled across the street. Following that, according to a detailed timeline released by the New York Police Department, he got on a bike and rode into nearby Central Park.

Surveillance cameras recorded him leaving the park a few minutes later on the Upper West Side, where he caught a taxi north to a bus station near the George Washington Bridge. Video showed him entering the station but not leaving.

WHO WAS BRIAN THOMPSON?

Thompson, 50, lived in Maple Grove, Minnesota. He had been the CEO of UnitedHealthcare, UnitedHealth Group's insurance unit, since April 2021. He was in New York for the company's annual investor conference when he was killed.

He had worked at different divisions of UnitedHealth for about 20 years. His wife Paulette Thompson said in a statement, "Brian was an incredibly loving, generous, talented man who truly lived life to the fullest and touched so many lives."

Thompson graduated from the University of Iowa in 1997 with degrees in business administration and accounting, according to his LinkedIn page.

UnitedHealth is the largest U.S. health insurer. The company, as well as Thompson and two other executives, was sued in May by a Hollywood, Florida, pension fund, which accused the company of insider trading after being made aware of a U.S. Department of Justice investigation into UnitedHealth.

WHAT EVIDENCE HAVE THE POLICE FOUND?

Police have not publicly identified the suspect.

Police have released a photo showing the suspect's face, as well as several images of him masked. Investigators have also recovered what they believe was his backpack from Central Park, according to media reports.

New York City Police Commissioner Jessica Tisch told CNN on Friday that police have gathered "a huge amount of evidence," including fingerprints, DNA evidence and camera footage of the suspect's movements throughout the city.

But DNA recovered from a phone, water bottle and energy bar wrapper all thought to be discarded by the gunman have not yet matched anyone in law enforcement databases, CNN reported on Monday, citing an unnamed official.

The suspect arrived in New York 10 days before the shooting on a Greyhound bus that originated in Atlanta and checked into a hostel using a fake ID, police said. While staying there, he kept his face covered - even during meals - but lowered his mask once to speak with a clerk, which yielded the photo of his face.

Surveillance video of the shooting suggests that he used a silencer, but Chief of Detectives Joseph Kenny told reporters that could not be verified by that video alone. The gun has not been located.

NBC News, citing two unnamed sources, reported on Monday that New York police detectives were headed to Pennsylvania to question a man there, in part because he was found with a gun similar to the one used in the shooting. According to the report, it was too soon to determine whether the Pennsylvania case was connected to Thompson's death.

The New York police have offered a $10,000 reward and the FBI another $50,000 for information leading to the capture of the shooter.

WHAT WAS THE MOTIVE?

Police do not yet know the motive, but they have said Thompson appeared to be deliberately targeted.

The words "deny," "defend" and "depose" were carved into the shell casings found at the scene, several news outlets have reported, citing sources. The words evoke the title of a book critical of the insurance industry published in 2010 titled "Delay, Deny, Defend: Why Insurance Companies Don't Pay Claims and What You Can Do About It."

Thompson's wife told NBC News that he had received some threats related to his job, but she said she did not know many details.

HOW ARE AMERICANS REACTING?

Thompson's murder unleashed a wave of frustration from Americans who have seen their health insurance claims denied, faced unexpected costs or paid more for premiums and medical care - all trends that are rising, according to recent data.

Americans pay more for healthcare than residents of any other country.

Many social media users responded to news of the killing with attempts to solve the mystery of the shooter's identity.

(Reporting by Reuters staff; editing by Jonathan Oatis)