New York, Dec 6 (IANS): The seconds before the shooting of the chief executive of UnitedHealthcare, 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, media reported, citing police sources.

"After the September 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," noted the New York Times report on Thursday.

New York City, the most populous in the US, 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, Xinhua news agency reported.

On Wednesday, cameras inside a Starbucks two blocks from the crime scene in Manhattan that the gunman visited minutes before the shooting captured his partially hidden face.

Others showed the gunman waiting for Brian Thompson, the chief executive and then recorded him fleeing on a bicycle into Central Park, where he disappeared.

By late Wednesday, the police had released at least five images of the suspect but had not announced arrests. They had not identified the shooter or a motive.

Despite the ubiquity of cameras across the five boroughs of the city, seemingly tracking New Yorkers' every move, the police have not always been able to harness their collective power to find suspects quickly, said the report.

"Even with New York's level of technology and surveillance, the police must rely on investigators who are keen observers and can identify someone by looking at their shape and movements," it added.