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The prelude, the crime and the aftermath were all caught on video. But investigators will need to use human intelligence to find the person who gunned down an insurance company’s chief executive.
The cameras caught the gunman standing alone for five minutes on West 54th Street, ignoring the early-morning rush of people streaming by.
They caught him again as he stood in the dark at 6:44 a.m. and locked into his target, Brian Thompson, the chief executive of UnitedHealthcare, who was walking on the other side of the street.
And they captured video of the gunman, who was dressed in black and wearing a gray backpack, crossing the street and walking up to Mr. Thompson. He appeared calm as he raised a gun, fired several times and then walked away.
The seconds before Wednesday morning’s shooting of Mr. Thompson, the fatal moments and the immediate aftermath were all captured on surveillance cameras, leaving investigators with a trail of digital evidence to help search for a man who was “proficient” with firearms, according to Joseph Kenny, the chief of detectives for the New York Police Department.
After the Sept. 11 attacks, the Police Department, with help from the federal government, poured resources into expanding its surveillance capabilities. New York City now has a vast system of cameras, both public and private, that the police can scour to locate people.
The city has “investigatory capabilities that are above and beyond most municipalities,” said Brittney Blair, a senior director in the investigations and disputes practice at K2 Integrity, which advises companies on risk management and security.