Thompson was gunned down outside of the New York Hilton Midtown on Wednesday morning ahead of healthcare giant UnitedHealth’s planned investor day. He was rushed to the hospital and declared dead shortly after.

Here’s what is known about the shooter so far:

He planned the attack

According to police, the suspect waited on 54th Street near the Hilton hotel for around five minutes before Thompson’s arrival around 6:45 a.m. Several pedestrians passed him before he fired multiple rounds at Thompson. Police commissioner Jessica Tisch called the shooting a “targeted, brazen attack” in a Wednesday press conference.

“I want to be clear at this time,” she said. “Every indication is that this was a premeditated, preplanned, targeted attack.”

The gunman’s physical description

The gunman was described by police as a light-skinned man wearing a cream-colored jacket, a black face mask, black-and-white sneakers, and a gray backpack.

He is also apparently fit enough to ride an e-bike, and knew the streets of New York City well enough to go from the scene to Central Park, where he disappeared.

After the attack, the gunman fled the scene, first into an alleyway between 54th and 55th Streets before heading toward Sixth Avenue and then getting on an electric Citi Bike. He rode north on the avenue toward Central Park, where he was last spotted on Center Drive—which is blocked to most automobiles—early this morning. Police will work with Citi Bike to access GPS data to track the shooter’s whereabouts.

Police also identified and recovered a cell phone at the scene.

Prior to the attack, the gunman went to a Starbucks a couple of blocks away on Sixth Avenue between West 51st and West 52nd Streets. Photos released by the NYPD show the suspect standing at the coffee shop counter in a black coat and black face mask wearing a gray backpack.

“Proficient in the use of firearms“

The suspect shot Thompson at least once in the back and once in the right calf. According to video footage from outside the hotel, the shooter fired three shots at Thompson, who had his back to the shooter. Thompson then took a couple steps and turned around before collapsing on the ground. Police recovered three live nine-millimeter rounds and three discharged nine-millimeter shell casings at the scene.

According to Joseph Kenny, the New York Police Department’s chief of detectives, the suspect is “proficient in the use of firearms,” as he was able to quickly clear a jam in his gun after he started shooting and then continued firing at Thompson. 

A source familiar with the matter told CNBC the gunman’s firearm has a silencer. Kenney said police have not been unable to confirm the use of a silencer from the surveillance footage, but it will be part of the investigation.

$10,000 reward

Police said people can continue to go about their daily lives but should report suspicious activity to Crime Stoppers. They have released fliers with surveillance photos of the shooter with a firearm and on the Citi Bike, though neither show his face. Officials have offered a $10,000 reward to individuals able to share information about the shooting.

The Rockefeller Center Christmas tree lighting ceremony is scheduled for tonight at around 8 p.m., will go on as usual. NYPD chief of department Jeffrey Maddrey said there will be a large police presence as there is every year, which include a plain clothes detail and intel division.

“This is a terrible event, but we’re going to go on, and people are going to enjoy the tree lighting tonight,” he said.