But questions remain about the events leading up to Saturday's bombings in New York and Seaside Park, New Jersey, and the discovery of pipe bombs Sunday night in Elizabeth, New Jersey.
Authorities believe the "main guy" has been caught, but the investigation continues to determine if Rahami had help.
Though FBI Assistant Director William F. Sweeney Jr. said there is "no indication" of an active operating cell in the New York area, evidence suggests Rahami was not acting alone, sources told CNN.
Surveillance video shows a man believed to be Rahami with a duffel bag in the area where an unexploded pressure cooker was found in New York's Chelsea neighborhood.
After he leaves, the video shows two other men removing a white garbage bag believed to contain the pressure cooker from the duffel bag and leaving it on the sidewalk, according to a senior law enforcement official and another source familiar with the video.
Investigators want to talk to the two men but appear to have moved away from the idea that the pair had been involved. New York police Commissioner James O'Neill
described the men as "strolling" along the street and seeming "incredulous" when they took the bag.
Lenny DePaul, a US Marshals Service former commander, told CNN that investigators would be asking Rahami whether he had any help.
"The real question is: Is there anyone else out there? Was this him solely on his own? Is this a lone wolf or a known wolf that's slipped through the cracks?"
Investigators will likely look to leverage his personal relationships to get information, DePaul said.
"Is there an ability to say: If you don't work with us, everyone around you who may have been complicit may be hit with a conspiracy charge (that may happen anyway) so there's leverage now that he's here," DePaul said.
If Rahami is not a lone wolf, where's the rest of the pack?
Is Rahami affiliated with a terror group?
A notebook found in Rahami's possession when he was taken into custody contained ramblings, including references to previous terrorists, such as the Boston Marathon bombers
, and Yemeni-American cleric Anwar al-Awlaki
, who was a spokesman for al Qaeda in the Arabian Peninsula before a CIA drone strike killed him in 2011.
Rahami was born in Afghanistan and traveled home often -- common for immigrant families. He is married to a woman from Pakistan, who was in the United States recently but left just before the bombings.
Investigators will be looking into his travels to both countries -- especially to areas recognized as Taliban and al Qaeda strongholds -- to see if he was radicalized abroad.
ISIS -- which claimed the Minnesota mall stabbings over the weekend
-- is less prominent in these countries than terrorist groups such as Pakistan's Tehreek-i Taliban
, the Afghan Taliban and al Qaeda.
The Afghan Taliban denies any involvement in the bombings and any ties with Rahami, said the group's spokesman, Zabiullah Mujahid.
And the reference in the notebook to Awlaki -- a source of inspiration for several terror attacks -- appears to bolster an emerging view among investigators that this weekend's attacks weren't ISIS-inspired, at least not in whole.
Former New York state homeland security adviser Michael Balboni told CNN it appeared Rahami "didn't have a plan B or a plan C."
"This has the flavor of someone who was self-radicalized and perhaps who was inspired but not instructed," he said.
Evan Perez, CNN's justice correspondent, said authorities would be looking at whom Rahami was meeting and associating with when he was abroad and whether they could have taught him to make a bomb.
Rahami didn't immediately cooperate with police, but investigators expect to try to talk to him again on Tuesday, a law enforcement official said.
Why wasn't Rahami on a watch list?
Perez said Rahami had not aroused any kind of suspicion that he might have been radicalizing.
"They have hundreds of young men who are attracted to ISIS or following supporters of different terrorist groups and are speaking out online, doing things on social media -- he was not one of these people."
The FBI did discuss Rahami with his father once, in 2014, after the younger Rahami was arrested on suspicion of stabbing one of his relatives, two US officials said Tuesday.
That interview stemmed from a tip alleging that Rahami's father was calling his son a terrorist, the officials said. However, there were conflicting reports about who initiated the contact. The father told reporters Tuesday that he contacted the FBI to express concerns about his son.
In the FBI interview, the father downplayed his concern, the two US officials said. The FBI ran more checks but never interviewed Ahmad Rahami, according to officials. Ultimately, federal investigators believed it was just a domestic dispute, officials said.
Rahami was never charged in the incident; a grand jury didn't find sufficient evidence to indict him, according to court documents.
At the time, Rahami had just returned from an extended trip to Pakistan and Afghanistan, one of several he had made to the region.
According to an official who reviewed Rahami's travel and immigration record, he had spent several weeks in Pakistan and Afghanistan in 2011 when he married. He was also in Pakistan almost a year -- and visited Afghanistan again -- from April 2013 until March 2014.
Rahami was questioned every time he returned from Afghanistan to the United States -- as is standard procedure -- and received secondary screening on both visits, telling officials he was visiting family and satisfying whatever concerns they had.
The law enforcement official said Rahami first came to the United States in January 1995, several years after his father arrived seeking asylum. The official said Rahami was given a US passport in 2003, while a minor, and again in 2007 after he said he lost his first one. However, Rahami only became a naturalized US citizen in 2011.
What did his family know?
Rahami's family lives above First American Fried Chicken in Elizabeth, the city's mayor says. The family has a history of clashes with the community over the restaurant, which used to be open 24 hours a day, Mayor Chris Bollwage said. Investigators searched the building Monday, Bollwage said.
Perez said investigators would be asking family members what they had noticed.
"Was he making trial runs at this? Where was he doing that? If he was making these bombs, was his house or home a bomb lab, and how did no one notice? How did no one -- his brother, his father, his family? He lived with them. Those are questions right now that are being asked of his family members and anybody who saw any changes in his demeanor in the last few months."
The family alleged discrimination and harassment in a lawsuit against the city and its police department in 2011, arguing that officials conspired against them by subjecting them to citations for allegedly violating a city ordinance on hours of operation.
Bollwage said Monday a 2012 ruling on the case favored the city, adding that the family's restaurant was "disruptive in the city for many, many years."
In a Facebook post Monday, a family member asked for privacy.
"I would like people to respect my family's privacy and let us have our peace after this tragic time," wrote Zobyedh Rahami, who's believed to be Rahami's sister.
Where is his wife?
Rahami's wife left the United States a few days before this weekend's bombings, and US officials want to speak with her, a law enforcement official said on condition of anonymity.
The official didn't provide details about her travels but said authorities are working with officials in Pakistan and the United Arab Emirates to gain access to her.
Her timeline in the United States wasn't immediately clear. Rahami had tried earlier this decade to petition to bring his wife to the United States from Pakistan, though it wasn't clear when he succeeded.
A law enforcement official told CNN that Rahami filed the paperwork in 2011, and it was approved in 2012.
Then, in 2014, Rahami contacted the office of US Rep. Albio Sires, D-New Jersey, from Islamabad, Pakistan, saying he was concerned about his wife's passport and visa. It turned out her Pakistani passport had expired and the consulate wouldn't give her an immigrant visa until the passport was renewed, Sires said.
Once the passport was renewed, she found out she was pregnant, and officials told her they wouldn't give a visa until she had the baby, Sires said. They also told her an immigrant visa would be needed for the baby after the birth.
At that point, Rahami claims the consulate told him to go back to Karachi, Pakistan, but he claimed it was too dangerous to go there. The congressman doesn't know what happened after that.
How are the New York and New Jersey attacks connected?
Initially, a garbage can explosion near a Marine Corps charity race in Seaside Park, New Jersey, seemed to be an isolated incident. Two other unexploded bombs were found nearby, and no one was wounded in the blast.
Then came another blast Saturday night in West 23rd Street in Chelsea, injuring 29 people. As law enforcement cordoned off the area, investigators found a pressure cooker four blocks away on West 27th Street. The video of the man with the duffel bag -- thought to be Rahami -- shows him in both locations.
Authorities have said Rahami is "directly linked" to the Seaside Park and Chelsea bombings.
Sources told CNN he is also believed to be connected to pipe bombs found Sunday night in Elizabeth, New Jersey, though there is no direct evidence.
Rahami's last known address was in Elizabeth.
The five pipe bombs were found in a backpack outside a neighborhood pub --- one later detonated as bomb technicians deployed a robot to examine them.
What do the devices tell us?
The pressure cooker bombs found at the 23rd Street and 27th Street locations in Manhattan contained the homemade explosive hexamethylene triperoxide diamine, or HMTD, according to law enforcement officials. It is a highly unstable explosive similar to TATP, used in the 2005 London bombings
The ingredients are easy to obtain, and recipes to make it are accessible online. Investigators believe Rahami used common precursor chemicals to make those explosives; now they are trying to find out where he purchased the ingredients, according to the officials.
CNN's Perez said it appeared Rahami did not have great expertise because the devices didn't work as well as they should have.
"Some of them were pipe bombs, some of them were pressure cooker bombs with cell phones to detonate. So the question is: How did he come up with this recipe? Who taught him to do this?"