New York police are still scouring the area for clues as to who is responsible for Saturday night's explosion in Manhattan's Chelsea neighborhood.
"We know it was a very serious incident, but we have a lot more work to do to be able to say what kind of motivation was behind this," New York Mayor Bill de Blasio told reporters Sunday.
Pressure cooker found blocks away
A few blocks from the site of the explosion, investigators found a pressure cooker with dark-colored wiring, connected to what appears to be a cellphone, according to CNN.
It was taken away from the scene by a bomb removal robot and New York City police said Sunday night that they've blown up the device.
Officials said the FBI Laboratory in Quantico, Virginia, will conduct a forensic examination of the device.
Law enforcement officials also said Sunday that they found residue from the explosive, Tannerite. Tannerite is often used for target practice and can be legally purchased in sporting goods stores.
Cell phones were found at the site of both the New York and New Jersey bombings, but not Tannerite residue was detected in New Jersey.
Surveillance video shows man dragging duffle bag
Surveillance video shows a man dragging a bag near the site of the explosion on West 23rd just 40 minutes before the blast Saturday night, multiple local and federal law enforcement officials told CNN.
Just 10 minutes later, officials said video shows what appears to be the same man on West 27th. In the video, the man leaves the bag where authorities say they found the pressure cooker.
According to CNN, after that man left, two other men can be seen removing white garbage bag from the duffle bag.
So far, investigators have not determined the relationship between the original man with the duffle bag and the two men who showed up later on in the surveillance footage.