The gunman struck on one of New York’s busiest streets. He shot once in the back of his target, the 50-year-old CEO of the health insurance company. And then he cleared a jam in the gun and fired two more times before escaping on a Citi Bike.

Who is the cyclist assassin who is now on the run? An injured health insurer or a cold-blooded killer? Or is another motive revealed?

Here’s everything police and witnesses have reported about the killer so far:

The hit and the shooter

Surveillance footage shows the killer “lying in wait” at 54th Street and Avenue of the Americas outside the New York Hilton Midtown for five minutes, blending in with the morning’s hustle and bustle.

Thompson was scheduled to speak at a UnitedHealthCare investor conference at the hotel and his schedule was widely known.

The shooter appeared to have known that Thompson would use the hotel entrance on 54th Street.

At 6:45 a.m., the assassin struck – he shot Thompson in the back, methodically cleared a weapons jam, and then fired again. The CEO collapsed and suffered fatal injuries to his back and calf.

Police recovered three spent cartridge cases, three live cartridges and, interestingly, a dropped mobile phone from the crime scene. The weapon, which was fitted with a silencer, left witnesses stunned – no one heard any shots in the morning chaos.

Short vacation on two wheels

In an escape befitting The Jackal, the fictional assassin in Frederick Forsyth’s best-selling novel, the shooter fled the scene on an electric CitiBike, New York’s bicycle-sharing system.

His escape route first took him on foot through Ziegfeld Alley across from the Hilton, then he hopped on a Citibike and rode half a mile to Central Park.

He was last seen wearing a black hat, black jacket, black ski mask, black pants, black sneakers with white soles and carrying a gray backpack.

Police describe the shooter as being 1.85 meters tall and of a tall, slim build.

The goal

Thompson, 50, was a married father of two from Minnetonka, Minn., with a long career in health care. He was a 20-year veteran of UnitedHealthcare, which he joined after seven years as a management consultant at PWC. At United, he led various business units, including as CEO of Medicare and other government program divisions before becoming CEO of the largest health insurance company in the world.

He was accused of insider trading in a lawsuit filed by the City of Hollywood Firefighters’ Pension Fund. The Daily Mail reportedabout allegations that he made $15.1 million by selling stock before a Justice Department investigation into UnitedHealthcare was announced. Democratic Senator Elizabeth Warren had asked the SEC to investigate the claims. Dow Jones reported. Public records show UnitedHealthcare filed a motion to dismiss the case a week ago.

Why was Thompson targeted?

New York City Detective Chief Joseph Kenny declined to speculate Tuesday morning. “The motive for this murder is unknown at this time, but based on the evidence we have so far, it appears that the victim was specifically targeted,” he said. “But at this point we don’t know why.”

Thompson’s widow, Paulette, revealed that he had received threats – possibly related to his role as head of the world’s largest health insurance company, with 52 million customers around the world, including 90 percent in the United States

“There had been some threats,” she said NBC News. “Basically, I don’t know, a lack of coverage? I don’t know the details. All I know is that he said there were some people who threatened him.”

Could the attacker be a disgruntled customer angry about rejected claims? An employee holding a grudge? Or was it corporate rivalry or sabotage?

Experts point out that the killer’s use of a silencer, his skill in correcting a weapon malfunction and his calculated escape are considered signs of a professional.

But the dropped phone and weapons issues are fueling speculation that it could have been a lone amateur driven by desperation, obsession or an unknown motive.

Questions that investigators must answer

The phone: Was it a mistake or a diversionary tactic? Tracing his data could reveal the killer’s identity.

The threats: Who sent them and how credible were they? Thompson’s wife’s cryptic comments suggest her husband may have known he was in danger.

The silencer: Where and how did the shooter acquire it? Such devices are regulated and provide another path to follow.

The Citi Bike: Where was it posted? Did the shooter use his own information to get this information? The bikes will only be given to members of the ride-sharing system or to occasional users who insert their credit card at a dock. Police have not said whether they found the bike. If so, they can immediately determine where and when the dock was unlocked from a dock. However, if this is not the case, the bikes do not have integrated GPS tracking.

The big picture

Was this murder the ultimate act of rage against America’s often-angry health insurance system? Or the calculated elimination of an influential executive?

What is clear is the shooter’s audacity – a murder in broad daylight on one of Manhattan’s busiest streets. And now an epic manhunt is underway in America’s largest city.