The FBI has released an image of two men who took a suitcase that held a bomb that did not explode in New York City.
Federal prosecutors have charged Ahmad Khan Rahami with setting a bomb in New Jersey and two in New York. One of the bombs left in Manhattan did not explode.
The FBI issued a poster showing "two unidentified individuals" who investigators want to talk to.
The agency said the men were seen on Saturday night removing the bomb from a piece of luggage, then leaving the device behind while taking the suitcase.
Investigators have said the two men are being sought as witnesses, not suspects.
The image was captured on CCTV between 8pm and 9pm on West 27th Street between 6th and 7th Avenues, the FBI said.
Earlier, authorities said Rahami vowed to martyr himself rather than be caught after setting off explosives and hoped "the sounds of bombs will be heard in the streets".
Criminal complaints in Manhattan and New Jersey federal courts provided chilling descriptions of the motivations that authorities said drove the Afghan-born US citizen to set off explosives, including a bomb that injured more than 31 people when it blew up in a busy Manhattan street.
More details emerged about Rahami's past, including the disclosure that the FBI had looked into him in 2014, but came up with nothing.
According to the court complaint, a handwritten journal by Rahami, 28, that championed jihad, included a passage that said: "You (USA Government) continue your (unintelligible) slaught(er)" against the mujahideen, or holy warriors, in Afghanistan and elsewhere.
"Death to your oppression," the journal ended.
One portion expressed concern at the prospect of being caught before being able to carry out a suicide attack and the desire to be a martyr, the complaint said.
Another section included a reference to "pipe bombs" and a "pressure cooker bomb" and declared: "In the streets they plan to run a mile" - an apparent reference to one of the blast sites, a charity run in a New Jersey shore town.
There also were laudatory references to Osama bin Laden, Anwar al-Awlaki - the American-born Muslim cleric who was killed in a 2011 drone strike and whose preaching has inspired other acts of violence - and Nidal Hasan, the former army officer who went on a deadly shooting rampage in 2009 at Fort Hood, Texas, the complaint said.
Before the federal charges were filed, Rahmani was already being held on 5.2 million dollars' (£4m) bail, charged with the attempted murder of police officers during the shoot-out that led to his capture Monday outside a bar in Linden, New Jersey.
Rahmani remains in hospital with gunshot wounds.