The New York City police are currently examining surveillance footage to locate the shooter responsible for the murder of UnitedHealthcare’s CEO, Brian Thompson, during what investigators believe was a targeted attack outside a hotel in Midtown Manhattan on Wednesday morning.

Thompson, aged 50, suffered three gunshot wounds fired from behind by a masked assailant who appeared to wait several minutes for him to pass by the Hilton hotel, where the company was holding an investor conference. The reason behind the shooting is still unclear.

During an extensive manhunt, police are analyzing footage from various public and private security cameras to trace the gunman’s path before and after the incident. Images were shared with the public on Thursday.

Below is a timeline of the events as they unfolded. Note that all times are approximate.

Following the gunman’s movements

5 a.m.

A surveillance camera captures the shooting suspect outside the Frederick Douglass Houses, two public housing complexes located at 830 Amsterdam Avenue in New York’s Upper West Side, according to ABC News. The individual appears to be carrying a battery for an electric bike.

6:17 a.m.

Footage from cameras inside a Starbucks at West 56th Street and 6th Avenue, just two blocks from the hotel, shows the suspect at the counter, as reported by CBS News.

While his face is partially obscured, authorities are employing facial recognition technology to attempt to identify him, according to the BBC.

Analyzing video footage to find the shooter

6:39 a.m.

The suspect arrives at the New York Hilton Hotel at 237 W. 54th St. in Manhattan. Police believe he was aware of which door Thompson was likely to use and the time he would arrive. A video shows the suspect making a phone call outside the hotel while ignoring those passing by.

6:44 a.m.

Video footage captures Thompson crossing the street from his hotel towards the Hilton, as reported by CBS.

Details of the shooting incident

6:46 a.m.

Surveillance video reveals Thompson being shot outside the hotel. The attacker approaches from behind and shoots him in the back and leg at close range. A woman nearby flees as the shooter seems to clear a malfunction in his weapon before advancing closer to Thompson, who is now on the ground, and firing again.

The shooter then escapes across West 54^th Street and into a pedestrian passageway near the Ziegfeld Ballroom, located at 141 W. 54th St. Inside the passage, police recover a cellphone and a water bottle, which might have been bought at the Starbucks, according to CNN.

6:47 a.m.

Authorities receive a 911 call reporting the shooting. They later discover three bullet casings engraved with the words “deny,” “defend,” and “depose,” as stated by YSL News.

These phrases resemble the title of a 2010 book called “Delay, Deny, Defend,” authored by Jay Feinman, which discusses how health insurers deny claims to boost their profits, according to The New York Times.

6:48 a.m.

Reports indicate the shooter is seen riding an electric bike along the Center Drive path leading into Central Park.

7:12 a.m.

Thompson is pronounced dead at Mount Sinai West Hospital in New York.

Authorities have made several images of the shooter available to the public. In these images, the assailant can be seen wearing a dark jacket with a hood, a black mask, distinctive black-and-white sneakers, and a unique gray backpack, according to YSL News.

The police are utilizing numerous camera feeds to aid in identifying the shooter. Following the 9/11 attacks, New York’s surveillance efforts significantly increased, with support from the federal government, as reported by The New York Times.

The NYPD released recent images of an individual described as a “person of interest” whom they wish to question regarding the shooting.

These new photos depict someone in a hooded jacket and black backpack, distinct from the gray backpack worn by the shooter during the incident on Wednesday morning.

Authorities have offered a reward of up to $10,000 for information that leads to the arrest and conviction of the shooter.