Bombing suspect Ahmad Khan Rahami has been charged with five counts of attempted murder of a law enforcement officer following Monday's shoot-out, but could face other charges related to Saturday's blasts in New York and New Jersey.
Rahami, who was shot, is in "critical but stable" condition after undergoing surgery, police said.
Investigators are seeking to determine the motive for the Afghanistan-born suspect's actions, how he became radicalised and whether he received any training from terrorist groups.
CNN yesterday quoted a law enforcement source as saying that Rahami's wife, whom he married in Pakistan, left the US just days before the bombings. US officials are reportedly working with their counterparts in Pakistan and the United Arab Emirates to locate her.
Earlier media reports said the 28-year-old naturalised US citizen had travelled to Afghanistan and Pakistan in recent years, though there has been no evidence that he received military training while he was overseas.
Officials are examining the explosive devices left behind to see if they bear any similarities to those used by terror groups.
Rahami was arrested after a dramatic shoot-out with police on Monday morning in Linden, New Jersey, about an hour from Manhattan.
Police officers had responded to a call from the owner of a tavern who was suspicious of a bearded man sleeping in the doorway. An officer approached the man and told him to put his hands up. At that point, Rahami shot the officer in the abdomen and fled.
"He was firing his handgun indiscriminately as he was walking down the street," said police captain James Sarnicki. "At some point, our officers returned fire and we were able to take him down."
Video footage showed a dazed- looking Rahami, blood flowing from a right shoulder wound, being loaded onto an ambulance. The police officer who was shot escaped more serious injury as he was wearing a bulletproof vest.
Rahami is thought to be behind two bombings and two attempted bombings that took place over the weekend.
On Saturday morning, a pipe bomb exploded in a rubbish bin along the route of a charity run in New Jersey. Later that day, a bomb placed in a construction dumpster in Chelsea, New York, exploded, injuring 29 people.
An unexploded pressure-cooker bomb was discovered four blocks away from the blast site.
On Sunday, several devices were found near a train station in Elizabeth, New Jersey, near the home of Rahami and his family.
The bombs in Elizabeth were found after two men saw an abandoned backpack. When they opened it and saw what was inside, they called the police. Similarly, the second bomb in Chelsea was discovered after two passers-by who took a liking to the bag it was in removed the device without detonating it.
A resident who saw the pressure cooker-like bomb then called the police. Fingerprints lifted from the bomb led the police to Rahami, whose family runs a fried chicken restaurant.
