The mayor of New York has promised additional surveillance cameras around Times Square and throughout the tourist heart of the city, as police struggled to come up with footage that would help their investigation into the failed bomb attack.
Investigators travelled to Pennsylvania yesterday to get footage from a tourist who claimed to have filmed a suspicious person at the time of the car bomb, while in the city local businesses were being asked to hand over private security camera footage that may hold clues.
The mayor, Michael Bloomberg, promised scores more police cameras to add to the 82 that police currently have installed in the midtown area of the city, but which failed to capture the significant moments of the incident.
An SUV packed with propane tanks, petrol and fireworks was left a few blocks north of Times Square on Saturday evening, a time when the area was thronging with tourists headed for pre-theatre dinner. While the homemade bomb began smoking, it did not detonate, and police were able to evacuate the area and carry out a controlled explosion.
Yesterday, they released CCTV footage of a man seen a short distance from the car, who is shown taking off a shirt and stuffing it into a bag, and glancing over his shoulder in the direction of the car.
The white male, in his forties, is the nearest that surveillance cameras have been able to come to identifying a possible suspect, but Mr Bloomberg cautioned that there were other leads being pursued.
"There are millions of people who come through Times Square," he said. "This person happened to be in a position in which a camera got a good shot of him, and maybe he had something to do with it, but there's a very good chance that he did not."
The authorities have been sceptical of claims from a Pakistani Taliban group which claimed responsibility on Sunday.
Had the bomb gone off, officials said, it would have split the SUV in two and sent shrapnel flying, causing significant casualties.
The car's journey into Times Square was caught on camera for only a few seconds. Following the 9/11 terrorist attacks in New York in 2001, the city installed thousands of surveillance cameras in Lower Manhattan, and the so-called "ring of steel" will also be extended into the midtown area that includes Times Square, following a federal grant. It is that work that the mayor referred to yesterday as being of top priority.
The ring of steel also includes licence plate readers and chemical weapons detectors, and has attracted the ire of civil liberties groups, who are fighting in the courts to get more information on the project.
Police have interviewed the owner of the SUV, who is not being trated as a suspect. Sources in New York and Washington said the registered owner of the Nissan Pathfinder sold the car about three weeks ago to a buyer he described as being 29 to 30 years old and of Hispanic or Middle Eastern appearance. Police have also been contacting local businesses to ask for video surveillance footage. The car was being driven with fake number plates, using plates from a car undergoing repairs in Connecticut. Its owner was traced using the vehicle identification number.
Eric Holder, the US attorney general, said it was too early to designate the incident as a terrorist attack, or to speculate whether it had foreign or domestic origins.
Janet Napolitano, the secretary of Homeland Security, told NBC's Today show that no suspects had been ruled out. "Every lead has to be pursued," she said. "I caution against premature decisions one way or another."
The SUV was filmed crossing an intersection near Times Square at 6.28pm on Saturday. Two minutes later, it was erratically parked and a local T-shirt vendor pointed it out to a police officer.