NY, NJ bombings: Suspect Ahmad Khan Rahami charged with attempted murder of officers.

The man suspected in Saturday's bombings in New York and New Jersey was captured on Monday after a frantic manhunt and shootout. Ahmad Khan Rahami, 28, was charged with five counts of attempted murder of a law enforcement officer after a shootout Monday with police in Linden, New Jersey, Union County Prosecutor Grace H. Park said. He is also charged with second-degree unlawful possession of a weapon and second-degree possession of a weapon for an unlawful purpose. Authorities said Rahami is "directly linked" to bombings Saturday in New York City and Seaside Park, New Jersey, and is believed to be connected to pipe bombs found Sunday night in Elizabeth, New Jersey, sources said.

"We have every reason to believe this was an act of terror," New York Mayor Bill de Blasio said Monday.

But many questions remain, chief among them, why did he do it? And, is anyone else responsible?

Rahami was captured after the owner of a bar in Linden, New Jersey, found him sleeping in the doorway of his bar Monday morning. Harinder Bains, owner of Merdie's Tavern, said he was watching CNN on his laptop from another business across the street. At first, he thought he was some "drunk guy" resting in the vestibule. Then, he recognized Rahami and called police.

"I'm just a regular citizen doing what every citizen should do. Cops are the real heroes, law enforcement are the real heroes," Bains told CNN's Anderson Cooper.

When officers responded, Rahami pulled out a handgun and opened fire, striking an officer in the chest. A foot chase ensued, during which Rahami shot at a police car, causing a bullet to graze another office in the face.

The chase ended when Rahami was shot multiple times. He was taken to a hospital for surgery. Officers Angel Padilla and Peter Hammer were taken to the hospital for treatment of non-life threatening injuries.

Rahami was not initially cooperative with police who tried to interview him, a law enforcement official said.

Authorities believe the "main guy" has been caught but the investigation continues to determine if Rahami had help, sources told CNN.

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.

New York explosion: What we know -- and don't know

As the investigation continues, law enforcement has stressed there is no reason to believe a bomber is on the run.

Officer Angel Padilla and Officer Peter Hammer.

Rahami was not initially cooperative with police who tried to interview him, a law enforcement official said.

Authorities believe the "main guy" has been caught but the investigation continues to determine if Rahami had help, sources told CNN.

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. As the investigation continues, law enforcement has stressed there is no reason to believe a bomber is on the run.

The investigation

Initially, a garbage explosion at 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 New York's Chelsea neighborhood, injuring 29 people. As law enforcement cordoned off the area, investigators found a pressure cooker four blocks away.Dark-colored wiring was connected by silver duct tape to what appeared to be a cell phone. Ball bearings and BBs were among pieces of metal that appeared to be packed inside, a federal law enforcement official said. A handwritten note found next to it contained ramblings, including references to previous terrorists, including theSurveillance video shows a man believed to be Rahami dragging what appears to be a duffel bag with wheels near the site of the West 23rd Street explosion about 40 minutes before the blast, according to multiple local and federal law enforcement sources.About 10 minutes later, surveillance video shows the same man with the same duffel bag on West 27th Street, multiple law enforcement sources said.

A device at a second location in Chelsea appears to be a pressure cooker.

In the video, the man leaves the duffel bag where police later found the unexploded pressure cooker. 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 have not determined if those two men are connected to the man with the duffel bag, the sources said.

Rahami was identified Sunday afternoon through a fingerprint, a senior law enforcement official said. Evidence from the cell phone on the pressure cooker also led to Rahmani's identification.A traffic stop Sunday night of five people in New York led to searches and interviews in Elizabeth, New Jersey, said Sweeney with the FBI. Rahami's last known address was in Elizabeth, the same city where the backpack with explosives was found Sunday night.The latest bomb discoveryThe backpack with five bombs inside was found in a wastebasket around 9:30 p.m. on Sunday outside a neighborhood pub in Elizabeth, about 16 miles from New York City. Two men found the backpack about 500 feet from a train trestle and alerted police, officials said.

As bomb technicians deployed a robot to examine the devices, one of the bombs detonated. The remaining four were taken to an FBI laboratory at Quantico, Virginia, Elizabeth Mayor J. Christian Bollwage said.

Police checked all garbage cans in the immediate area but found no other suspicious items.

By Monday, authorities said they believed Rahami was linked to the explosion.

Who is the suspect?

Rahami first came to the United States in 1995 as a child, after his father arrived seeking asylum, and became a naturalized US citizen in 2011, according to a law enforcement official who reviewed his travel and immigration record.

Rahami traveled for extended periods to Afghanistan and Pakistan in the last five years, officials said. While in Pakistan in July 2011, he married a Pakistani woman. Two years later, in April 2013, he went to Pakistan and remained there until March 2014, visiting Afghanistan before returning to the United States.

Upon returning from both visits he told officials he was visiting family, satisfying any concerns immigration officials had at the time.

His family runs First American Fried Chicken in Elizabeth, the city's mayor said. 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.

In 2011, the family sued the city of Elizabeth, and its police department, alleging discrimination and harassment against Muslims stemming from disputes over the restaurant's hours. Investigators searched the building on Monday, Bollwage said.

'Bigger than ever' NYPD presence

The bombings came as New York hosts world leaders at the United Nations General Assemblythis week.

Heightened security across the city is common during the UNGA. But after the Chelsea bombing, Cuomo said 1,000 additional New York State Police officers and National Guard troops will be deployed to patrol bus terminals, airports and subway stations.

"You should know you will see a very substantial NYPD presence this week -- bigger than ever," de Blasio said.

Substantial police presence notwithstanding, life appears to have returned to normal, whether you call it resilience or resignation.

As President Obama said Monday,

"we all have a role to play as citizens" by making sure we don't succumb to fear.

People in the region are tough and resilient, he said.

"They don't get scared," he said. "That's the kind of strength that makes me so proud to be an American. And, that's the kind of strength that is going to be absolutely critical, not just in the days to come, but in the years to come."

CNN's Evan Perez and Shimon Prokupecz reported from New York, and CNN's Emanuella Grinberg and Holly Yan wrote this story. CNN's Rachel Crane and Linh Tran reported from Elizabeth, New Jersey, and CNN's Pamela Brown, Drew Griffin, Madison Park, Joe Sutton, Emily Smith and Max Blau also contributed

The Mariana DAngelo Editorial Group.