Three attacks in U.S. in 12 hours, but links remain uncertain

Last Updated Sep 19, 2016 8:41 AM EDT

NEW YORK -- A mall in Minnesota, a New York City neighborhood, and a charity race in New Jersey were all scenes of attacks within 12 hours of each other on Saturday, and investigators are scrambling to piece together the evidence in each. 

Investigators scrambled Sunday to find out who planted a bomb that rocked a bustling New York City neighborhood, scouring shrapnel, forensic traces and surveillance video for possible links to an unexploded pressure-cooker device found just blocks away. Twenty-nine people were injured in the blast. 

Just hours earlier in New Jersey,  a pipe bomb exploded in a seaside community before thousands of runners were to participate in a charity 5K race to benefit Marines and sailors.

In Minnesota, a man in a private security uniform stabbed nine people at a shopping mall, reportedly asking victims if they were Muslim before an off-duty police officer shot and killed him in an attack the Islamic State of Iraq and Syria (ISIS) claimed as its own.  

Here’s more on the investigations into the three attacks:

Chelsea blast

Hours after the Saturday night blast that injured 29 people in Manhattan, there seemed to be more questions than answers. All the injured had been released from the hospital by Sunday afternoon.

“We just know there was a bombing,” Mayor Bill de Blasio said at briefing at New York Police Department’s headquarters. “That much we do know.”  

Sources told CBS New York Sunday evening that the FBI made a car stop on the Belt Parkway in Brooklyn near the Verrazano Bridge. Several people were taken into custody but no details were released about the reason for the stop.

The FBI said in a statement that at 8:45 p.m., the FBI and NYPD conducted a traffic stop of a vehicle of interest in the investigation into Saturday’s bombing in Manhattan. No one has been charged with any crime. The investigation is continuing.    

On Monday morning, investigators said they were seeking Ahmad Khan Rahami, 28, in connection with the Chelsea bombing.

Sources tell CBS News that Rahami is also sought in connection with the bombing in Seaside Park, New Jersey, as well as five explosive devices found in a backpack near a train station in Elizabeth, New Jersey, the suspect’s hometown.

Gov. Andrew Cuomo, who toured the site of the blast in Manhattan’s Chelsea neighborhood, said it was not yet known whether the attacks were related to international terrorism. He said a second device found blocks away from the bombing appeared “similar in design” to the first.

That device -- described by a law enforcement official as a pressure cooker with wires and a cellphone attached to it -- was removed early Sunday by a bomb squad robot and was being examined by forensic experts. 

Officials have confirmed that the device that exploded was probably also a pressure cooker bomb set off by a cellphone.

Authorities have one person on surveillance video seen planting at least one of bombs in Manhattan, CBS News learned Sunday night. Authorities stress that he may or may not be the person who did this, but it is a solid lead.   

Officials say the bombs found in NYC were similar to the devices used in the Boston Marathon bombing.  

The Manhattan blast followed a pipe bomb explosion earlier Saturday in Seaside Park, New Jersey, before the start of a charity 5K race to benefit Marines and sailors. The devices contained different materials, officials said, but added that they weren’t ruling anything out yet. The race was canceled and no one was injured. 

Officials have said a cellphone was also used to detonate the New Jersey bomb.

The New Jersey device contained evidence of a black powder, while the device that exploded in Manhattan had residue from an explosive called Tannerite, said a federal law enforcement official, who spoke on condition of anonymity because he wasn’t authorized to discuss details of the ongoing investigation.

Tannerite is often used in target shooting to mark a shot with a cloud of smoke and small explosion.

CBS News homeland security correspondent Jeff Pegues reported that law enforcement sources are tracking down all kinds of leads, as they have received numerous claims of responsibility for the NYC attack.

Investigators were looking into whether the explosion in Chelsea is connected to a person who said he was “sick of gays” being oppressed, however and official later told the AP that that claim had been shot down by investigators.

The Saturday night bombing rocked Manhattan’s Chelsea neighborhood, a mostly residential area on the city’s west side known for its art galleries and large gay population. The explosion left many rattled in a city that had marked the 15th anniversary of the 9/11 terrorist attacks only aweek earlier.

On Sunday, a team of five FBI agents searched an Uber driver’s vehicle that had been damaged in the Manhattan blast, ripping off the door panels inside as they examined it for evidence.

The driver, MD Alam, of Brooklyn, had just picked up three passengers and was driving along 23rd Street when the explosion occurred, shattering the car’s windows and leaving gaping holes in the rear passenger-side door.

“It was so loud,” the 32-year-old Alam said. “I was so scared. There was a loud boom and then smoke and I just drove away.”

Alam said he hit the gas and tried to take his passengers to their destination in Queens, but pulled over along Madison Avenue and 39th Street. He went to a local police precinct to file a report for his insurance company and police contacted the FBI.

Witnesses described hearing a deafening blast, and surveillance video footage captured images of nearby windows being blown out by the explosion as people sprinted away from the scene.

“It was extremely loud, almost like thunder but louder,” said Rudy Alcide, a bouncer at a nightclub near the blast.

Members of the FBI’s Joint Terrorism Task Force were investigating the blast along with New York Police Department detectives, fire marshals and other federal investigators. As a precaution, Cuomo said he was deploying an additional 1,000 state troopers and members of the National Guard throughout New York City and police officials promised more officers on the streets ahead of a United Nations meeting on Monday to address the refugee crisis in Syria.

The first device, which exploded on West 23rd Street at about 8:30 p.m., appeared to have been caused by an explosive device placed inside a toolbox in front of a building undergoing construction.

The second device, found later inside a plastic bag on West 27th Street.

An NYPD official tells CBS News they were successfully able to pull the device apart. They did not have to blow up device.

In Los Angeles, Police Chief Charlie Beck asked Emmys attendees to remain vigilant in the wake of explosions in New York City and New Jersey.  Beck said there were no known credible threats to security in Los Angeles, but those attending Sunday’s Emmys in downtown Los Angeles were asked to report any suspicious activity.

Seaside Park, N.J. explosion 

Officials initially would not say if they believe the Saturday afternoon blast in Seaside Park was terror-related or had any connection with the Manhattan blast.

Special Agent Michael Whitaker, a spokesman for the FBI office in Newark, said state and federal investigators were canvassing the Seaside Park area Sunday and conducting interviews. He said travel restrictions imposed after the blast had been lifted.

He declined further comment, citing the ongoing investigation. New Jersey state police also wouldn’t comment and referred questions about the blast to the FBI.

Appearing Sunday on CNN’s “Inside Politics” with Jake Tapper, Gov. Chris Christie said state police had “some promising leads” but no suspects. The Republican governor said people should not jump to conclusions about who may be responsible for the blast or what the motive was.

Christie said that by his own definition, he personally considered the blasts“terrorism,” likewise a knife attack at a Minnesota mall.

No injuries were reported in the seaside explosion. The race had been scheduled to start shortly before the blast occurred, but was delayed due to the large numbers of people registering for the race and reports of an unattended backpack being found.

Officials noted that if the race had started on time, a “good number of people” would have been running past the area where the explosion occurred.

“The fortunate thing here in New Jersey is that no one was injured,” Christie said. “We pray for those people who were injured in those other attacks.”

A source tells CBS News that they have not yet definitively made the connection between the blast in the Chelsea neighborhood of New York City Saturday night that left more than two dozen injured, and the blast in Seaside. However, the source says both the Chelsea bombs and the Seaside Park bombs used cellphones as triggers.

Meanwhile, residents in Seaside Park hoped things would return to normal soon.

Joggers, walkers and bikers were out and about Sunday on the boardwalk and nearby streets. Some stopped to take pictures of the site where the blast occurred and of television trucks that remained in the area.

“It’s the first time I’m leery of walking around and everything,” borough resident Don Bernabe told the Asbury Park Press. “I walked by the first set of garbage cans back there coming this way, and it was weird, but that feeling went away. You never get that feeling around here. Ever.”

Another resident, Maggie Powell, voiced similar concerns.

“I have to admit, yes, this whole thing is pretty disconcerting. You don’t think these types of things can happen around here, but something like this reminds you it can happen anywhere. It’s sad, actually,” she said.

Minnesota shopping mall attack

None of the nine people who were stabbed in Saturday night’s attack received life-threatening wounds, St. Cloud police Chief Blair Anderson said. He said it doesn’t appear that anyone else was involved in the attack at the Crossroads Center in St. Cloud, which began at around 8 p.m. and was over within minutes.

At a news conference Sunday, FBI Special Agent-in-Charge Rick Thornton said the attack was being investigated as a possible act of terrorism and that agents were still digging into the attacker’s background and possible motives.

An ISIS-run news agency, Rasd, claimed Sunday that the attacker was a “soldier of the Islamic State” who had heeded the group’s calls for attacks in countries that are part of a U.S.-led anti-ISIS coalition.

It was not immediately clear if the extremist group had planned the attack or even knew about it beforehand. ISIS has encouraged so-called “lone wolf” attacks. It has also claimed past attacks that are not believed to have been planned by its central leadership.

Authorities didn’t identify the attacker, but the Star Tribune of Minneapolis said the man’s father identified him as Dahir A. Adan, 22. Speaking to the newspaper through an interpreter, Ahmed Adan, whose family is Somali, said his son was born in Africa and had lived in the U.S. for 15 years.

A spokesman for St. Cloud State University confirmed that Adan was a student there, but has not been enrolled since the spring semester. Spokesman Adam Hammer said Adan’s intended major was information systems, which is a computer-related field.

He said police told him at around 9 p.m. Saturday that his son had died at the mall, and that police had raided the family’s apartment, seizing photos and other materials. He said police said nothing to him about the mall attack, and that he had “no suspicion” that his son had been involved in terrorist activity, the newspaper reported.

Anderson said police had had three previous encounters with the attacker, mostly for minor traffic violations.

According to Anderson, the attacker, dressed in a security uniform and wielding what appeared to be a kitchen knife, began attacking people right after entering the mall, stabbing people in several spots inside the building, including corridors, businesses and common areas.

Five minutes after authorities received the first 911 call, Jason Falconer, a part-time officer in the city of Avon, shot and killed the attacker, whose name hasn’t been released. Anderson said Falconer fired as the attacker was lunging at him with the knife, and continued to engage him as the attacker got up three times.

“He clearly prevented additional injuries and potential loss of life,” Anderson said.

“Officer Falconer was there at the right time and the right place,” he said.

Anderson earlier said the man reportedly made at least one reference to Allah and asked a victim if they were Muslim before attacking them.

Leaders of the Somali community in central Minnesota united to condemn the stabbings. They said the suspect does not represent the larger Somali community, and they expressed fear about backlash over the attack.

Minnesota has the nation’s largest Somali community, with census numbers placing the population at about 40,000, but community activists say the population is much higher. The immigrant community has been a target for terror recruiters in recent years. More than 20 young men have left the state since 2007 to join al-Shabab in Somalia, and roughly a dozen people have left in recent years to join militants in Syria. In addition, nine Minnesota men face sentencing on terror charges for plotting to join the Islamic State group.

The attack in St. Cloud, a city of about 65,000 people 60 miles northwest of Minneapolis, began shortly after an explosion in a crowded New York City neighborhood injured 29 people. A suspicious device was found a few blocks away and safely removed. Hours before that, a pipe bomb exploded in Seaside Park, New Jersey, shortly before thousands of runners were due to participate in a charity 5K race. There was no immediate indication that the incidents were linked.

The mall remained closed Sunday. Of the nine victims -- seven men, a woman and a 15-year-old girl -- three remained hospitalized, officials said.

Photos and video of the mall taken hours after the incident showed groups of shoppers waiting to be released, including some huddled together near a food court entrance.

Harley and Tama Exsted, of Isle, were in St. Cloud to watch their son play in a college golf tournament and were in the mall when the attack happened.

“All of a sudden I heard pop, pop, pop,” Harley Exsted told the St. Cloud Times. “I thought someone tipped over a shelf. All of a sudden these people started running. I just saw everybody running our way.”

The couple were unharmed and said they helped another woman who was running from the scene to her car.

Falconer, who was shopping when he confronted the attacker, is the former police chief in Albany, which is about 15 miles northwest of St. Cloud, and the president and owner of a firing range and firearms training facility, according to his LinkedIn profile. His profile says he focuses on firearms and permit-to-carry training, and also teaches “decision shooting” to law enforcement students at St. Cloud State University.