How the NYPD will use cameras to find Brian Thompson’s killer

The cameras captured the gunman standing alone on West 54th Street for five minutes, ignoring the early morning rush of people streaming past.

They caught him again as he stood in the dark at 6:44 a.m. and caught sight of his target, UnitedHealthcare CEO Brian Thompson, who was walking across the street.

And they captured video of the gunman, dressed in black and carrying a gray backpack, crossing the street and walking toward Mr. Thompson. He appeared calm as he raised a gun, fired several times and then walked away.

The seconds before Mr. Thompson was shot Wednesday morning, the fatal moments and the immediate aftermath were all captured by surveillance cameras, leaving investigators with a trail of digital evidence that Joseph said could help find a man who was “practiced.” Kenny, the chief detective of the New York Police Department, knew how to handle firearms.

After the September 11 attacks, police invested resources to expand their surveillance capabilities with support from the federal government. New York City now has a vast system of public and private cameras that police can use to track people down.

The city has “investigative capabilities beyond those of most municipalities,” said Brittney Blair, senior director of the investigations and dispute resolution practice at K2 Integrity, which advises companies on risk management and security issues.