New York, Dec 5 (IANS): Investigators have found eerie messages scratched on the bullet casings found where the CEO of the largest US health insurance company was killed that could hold clues to the shooter's motivation.

Police said on Thursday that the words “deny,” “depose”, and “defend” were found written on three bullets.

The words, “deny” and “depose”, are terms used by insurance companies when they refuse to pay for treatments claiming they are not covered by the policies.

This could lead to a person with a grievance against United Healthcare (UHC), which Brian Thompson led till Wednesday when he was shot outside a Hilton hotel in mid-town New York where his company was holding an investors’ meeting.

Police sought search warrants looking for the mystery gunman who waited outside the hotel, shot him from about three metres away, unjamming the .9 mm gun with a silencer, and fled on a for-hire electric bicycle.

The masked man's trail went cold at the nearby Central Park and a massive manhunt was on.

Three live bullets, three spent shells, a water bottle from a Starbucks coffee shop, and an abandoned mobile phone found by the police near the site of the shooting may hold clues.

The words, “deny,” “depose”, and “defend”, had some similarities to the title of a book criticising the insurance industry, “Delay Deny Defend: Why Insurance Companies Don’t Pay Claims and What You Can Do About It,” by Jay Feinman.

A blurb for the book on Amazon described the author as a legal scholar and insurance expert and said it deals with how “insurance companies now often try to delay payment of justified claims, deny payment altogether, and defend these actions by forcing claimants to enter litigation”

A Senate panel’s report criticised UHC for a high rate of denial of claims.

Thompson, 50, became the CEO of the Minnesota-based UHC in 2021 after working his way up during his 20-year career with the company.

His annual salary was nearly $10 million heading the company with 140,000 employees and annual revenues of $281 billion.

After waiting for Thompson, the gunman shooting from behind him hit him in the leg and chest.

Security videos show him quickly resetting the gun after it jammed and resuming firing.

Police Department Chief Joseph Kenny said, “It does appear he is proficient in the use of firearms, as he was able to clear the malfunction pretty quickly”.

The annual ritual of lighting the Christman Tree at the nearby Rockefeller Centre went off peacefully Wednesday night with tens of thousands jamming the streets around the area after reassuring messages from officials that the shooting was targeted and not a random crime.