Dec 7 (Reuters) - Authorities have identified the man

suspected of killing UnitedHealth ( UNH ) executive Brian

Thompson and are closing in on him, New York City Mayor Eric

Adams was quoted as saying on Saturday by the New York Post.

"The net is tightening," Adams told reporters at a Police

Athletic League holiday party in Harlem, according to the Post.

He declined to name the suspect.

Thompson, 50, who became CEO of UnitedHealth's ( UNH ) insurance

unit in April 2021, was shot in the back around 6:45 a.m. ET

(1145 GMT) on Wednesday in what police described as a targeted

attack by a masked assailant lying in wait.

The murder occurred just before the company's annual

investor conference at the Hilton hotel on Sixth Avenue.

The shooting sparked a massive manhunt for the gunman, who

fled on foot wearing a hooded jacket, balaclava and gray

backpack before mounting an electric bike and riding into

Central Park, police said.

Adams was quoted by the Post as saying the police were

withholding the suspect's name for now to deny him any

advantage.

"We don't want to release that now," the mayor said. "If you

do, you are basically giving a tip to the person we are seeking

and we do not want to give him an upper hand at all. Let him

continue to believe he can hide behind the mask."

"We revealed his face," he continued, referring to security

camera photos and video released after the murder. "We're going

to reveal who he is and we're going to bring him to justice."

New York police said on Friday they believe the suspect had

left New York City, after video emerged showing him climbing

into a taxi that took him to a bus station.

"We have video of him entering the Port Authority Bus

Terminal. We don't have any video of him exiting so we believe

he may have gotten on a bus," New York Police Department Chief

of Detectives Joseph Kenny told CNN. "Those buses are interstate

buses. That's why we believe he may have left New York City."

The circumstances of the attack suggested it was

premeditated and planned, police said, with video showing the

gunman ignoring other pedestrians while appearing to wait for

Thompson. The shooter's motive was not yet known.

Security video showed the shooter behind Thompson, raising

his handgun and firing at his back. Thompson, a married father

of two, suffered gunshot wounds to his back and leg and was

pronounced dead at a hospital shortly after the attack.

UnitedHealth ( UNH ) is the largest U.S. health insurer, providing

benefits to tens of millions of Americans, who pay more for

healthcare than people in any other country.