[Update: 2:30 a.m. ET] Law enforcement officials early Monday pored through evidence, including a 20-second video, after a failed car bombing attempt in Times Square over the weekend.

[Update: 10:28 p.m. ET] Investigators have obtained a videotape from a Pennsylvania tourist who believes he may have caught a suspect's image on camera, according to New York Deputy Police Commissioner Paul Browne.

[Update: 8:44 p.m. ET] Material found in a gun locker inside the Nissan Pathfinder was "non-explosive-grade fertilizer incapable of blowing up," Deputy Commissioner Paul Browne tells CNN. Still, the gasoline cans and propane tanks that also were in the vehicle "could have exploded with enough force to split the vehicle in two and produce a fireball," Browne said. The vehicle's contents were "capable of producing human casualties and broken windows," but did not have enough force "to take down a structure, in the opinion of NYPD bomb experts," Browne said.

[Update: 7:40 p.m. ET] The Nissan Pathfinder belongs to someone who lives in the tri-state area, a New York police official tells CNN's Susan Candiotti. This contradicts what a federal law enforcement source told CNN earlier Sunday.

[Update: 6:55 p.m. ET] Authorities have identified and are attempting to speak with the owner of the Nissan Pathfinder, a law enforcement source with knowledge of the investigation says, according to CNN Correspondent Deb Feyerick.

Police say this is one of two clocks that were part of a device in the attempted Times Square car bombing.

[Update: 6:13 p.m. ET] New York City police have released a picture showing one of two clocks they say were part of the apparent bomb inside the Nissan Pathfinder. The clocks, on the floor of the vehicle's back seat, were connected by wires to a can containing M-88 firecrackers, and that can was between two gasoline containers, New York Police Commissioner Ray Kelly said. Kelly also said that the unknown substance in a gun locker found in the vehicle may be fertilizer. Investigators believe the clocks were supposed to ignite the firecrackers, causing the gasoline containers to ignite, which would then explode three propane tanks that also were in the vehicle and "have some effect on that rifle box," which also contained wires and more M-88s, Kelly said.

[Update: 5:37 p.m. ET] The Nissan Pathfinder's vehicle identification number has helped investigators determine that the vehicle is not from the  immediate tri-state area, a federal law enforcement source tells CNN's Susan Candiotti. New York City police earlier said that the Connecticut license plate found on the Nissan did not belong to that vehicle, but rather to a truck that had been left at an automobile salvage yard near Bridgeport, Connecticut.

[Update: 4:33 p.m. ET] President Obama, speaking in Venice, Louisiana, where he is monitoring the oil slick in the U.S. Gulf Coast, promises "to see that justice is done" after the failed car bombing in Times Square.

[Update: 4:02 p.m. ET] If the car bomb had detonated, it would have caused casualities and a "significant fireball," New York Police Commissioner Ray Kelly said. "I'm told the vehicle itself would have at least been cut in half," Kelly said at a news conference. "You have large numbers of pedestrians in that area, so, yeah, we were lucky that it didn't detonate."

[Update: 4:00 p.m. ET] President Obama, who is in Louisiana to monitor the growing oil slick in the U.S. Gulf Coast, took some time during that visit to speak with New York City Mayor Michael Bloomberg by phone, White House spokesman Robert Gibbs says.

[Update: 3:45 p.m. ET] The New York Police Department bomb squad has used an explosive charge to open a gun locker that was in the back of the vehicle, Commissioner Ray Kelly said. The gun locker was 55 inches tall, 32 inches wide and contained "eight bags of an unknown substance" and a compartment containing a "bird's nest of wires and M-88 firecrackers," Kelly said. He said the police department is working with New York's Department of Environmental Protection to identify the substance found in the bags. He said the locker weighed about 70 pounds.

[Update: 3:39 p.m. ET] Law enforcement officials are examining video that may have captured the image of a suspect in the attempted Times Square car bombing,  the New York City police commissioner said. "We're currently examining video that shows a white male in his 40s, in Schubert Alley, looking back in the direction of West 45th Street," Commissioner Ray Kelly told a news conference. "He also was seen shedding a dark-colored shirt, revealing a red one underneath. He put the darker one into a bag that he was carrying," said Kelly, who added the video was captured about a half block from where the vehicle containing the bomb was parked.

[Update: 1:27 p.m. ET] A used auto parts company, Kramer's Used Auto Parts of Stratford, Connecticut, may hold clues for the investigation, a law enforcement source told CNN. CNN Affiliate WTNH of New Haven, Connecticut, reports that several uniformed police officers have been seen in and around the facility.  The Connecticut Post, in a report published on its website, quoted federal authorities posted outside the business as saying they would have a statement soon. The company has not been linked to the New York incident, but it may lead to clues about those responsible. New York City police earlier said that the Connecticut license plate found on the Nissan did not belong to that vehicle, but rather to a truck that had been left at an automobile salvage yard near Bridgeport, Connecticut.

[Update: 12:35 p.m. ET] Sen. Charles Schumer, Democratic senator from New York, talked with CNN's Candy Crowley about the possibility of terrorist ties: "The odds are quite high that this was a lone wolf. Could it have been a lone wolf connected to some terrorist organization? Possibly. Probably not. Could it have been a lone wolf who had that ideology and was doing it on his own? Possibly. Could it have been someone else who didn't have terrorist ideology at heart but might have been just mentally ill or whatever? That's possible as well. But given the nature of the explosive and given the fact that there was no chatter on the lines, signs point to — and again it's preliminary — that this was not part of any terrorist plot by al Qaeda or another known terrorist organization."

[Update 11:31 a.m. ET] New images and video of the scene in Times Square as police evacuated people and investigated the car bomb late Saturday and into Sunday morning — iReporter Matthew Derby was vacationing in New York from Hawaii when he witnessed the scene. Read more as he describes being evacuated

[Update: 11:30 a.m. ET] New York car bomb: What happened? See the location, details on what was found inside the SUV and investigation next steps

[Update 10:14 a.m. ET] A VIN number has been recovered from the Times Square vehicle, a federal law enforcement offical tells CNN's Carol Cratty.

[Update 9:42 a.m. ET] Napolitano: car bomb being handled as possible terrorism attack

WASHINGTON (CNN) - Homeland Security Secretary Janet Napolitano said Sunday that the car bomb found in New York City's Times Square was being handled as a "potential terrorist attack."

In an interview on CNN's "State of the Union," Napolitano said it was too early to know who was responsible for leaving a vehicle laden with explosives in the symbolic heart of the nation's most populous city.

"We're taking this very seriously," Napolitano said, noting that the New York police, FBI and federal Joint Terrorism Task Force were involved in the investigation. "We're treating it as if it could be a potential terrorist attack."

[Update 8:39 a.m. ET] Watch video of the SUV as it's towed away from Times Square

[Update 7:10 a.m. ET] Plate on Times Square SUV came from Connecticut junkyard
The Connecticut license plate found on the Nissan Pathfinder at the center of the Times Square bomb scare came from an automobile junkyard near Bridgeport, a law enforcement official told CNN on Sunday. Under Connecticut law, plates must be returned to a local Department of Motor Vehicle branch or to a Connecticut state trooper if a car is to be junked for scrap metal.
- From David Fitzpatrick, CNN

(CNN) - On Sunday, most of the areas around Times Square shut down after a car bomb was found had reopened, even as the investigation continues. Authorities are still going through video from dozens of surveillance cameras in Times Square to determine who left the Nissan Pathfinder with its engine running and hazard lights flashing on a street shortly after 6 p.m. Saturday. Inside the vehicle, police found three propane tanks, two filled five-gallon gas containers, two clocks with batteries, consumer-grade fireworks and a locked metal box that resembled a gun locker.