BUCKS COUNTY, Pa. — Emir Balat and Ibrahim Kayumi have a lot in common: They’re both teenagers. They’re both first-generation Americans. Both live on tree-lined streets in the affluent suburbs north of Philadelphia.

“Nothing crazy happens around this area,” said Logan Lombardi, who went to high school with Kayumi.

For all their similarities, however, authorities say the only known link between the pair is what they did together last Saturday: attempt what investigators describe as an ISIS-inspired attack by throwing explosive devices at a protest outside New York City Mayor Zohran Mamdani’s residence.

Federal prosecutors allege that Balat, 18, and Kayumi, 19, drove to Manhattan from Pennsylvania the morning of March 7, parking a few blocks away from Gracie Mansion before slipping into a crowd that included participants in an anti-Islam demonstration and a group of counterprotesters. The pair was arrested after Balat threw two jars packed with explosive materials at protesters and law enforcement, according to prosecutors.

Neither of the devices detonated, and no one was injured. Balat and Kayumi are being detained on several federal charges, including attempting to provide support to the Islamic State, after prosecutors said the pair made statements about the terrorist group.

Body-camera video from the New York City officers who arrested Kayumi shows him responding “ISIS” to someone in the crowd asking why he had done it, according to a federal complaint.

After waiving his Miranda rights, prosecutors said, Balat pledged his allegiance to the Islamic State and told authorities that he hoped to inflict more carnage than the 2013 Boston Marathon bombing, which left three dead and more than 260 others injured.

Lawyers for Balat and Kayumi did not immediately return requests for comment. Balat’s attorney, Mehdi Essmidi, told NBC News on Monday that Balat has “complicated stuff going on” and suggested that his client did not know Kayumi prior to Saturday.

“They’re strangers to each other,” he said.

Classmates recall a quiet, independent student

While authorities have not detailed how the teenagers knew each other, the two grew up roughly 4 miles apart in Bucks County, Pennsylvania.

Kayumi lives in Newtown, Pennsylvania, on a street lined with 4,000-square-foot brick homes, and manicured lawns. His parents emigrated from Afghanistan and became U.S. citizens in 2004 and 2009, according to CBS News.

On Thursday, no one answered the door, though a Mercedes sat in the driveway. Neighbors a few houses away told NBC News they didn’t know Kayumi or his family well and said they mostly kept to themselves.

Kayumi enrolled part time at nearby Bucks County Community College in September 2024, according to a college spokesperson.

Earlier that year, he had graduated from Council Rock High School North, which has a football field and track, roughly a dozen newly paved tennis courts and a student parking lot packed with luxury cars. Students said the area is not known for the violence prosecutors now allege.

“The high school and the town — people are pretty affluent,” said former classmate Connor McCormick. “There’s not really a whole lot of controversy at all.”

The high school said in a statement that “there is no evidence that he has posed a threat to any Council Rock schools” and encouraged concerned students to consult with their school counselors.

Another former classmate, Matt — who asked that his last name not be published due to fears of retaliation — said he and Kayumi were in smaller classes for children with learning disabilities.

Matt said that although he and Kayumi saw each other a lot, their conversations were typically brief and one-sided.

“He definitely was very quiet,” Matt said. “He would not talk unless you tried to talk to him, you know what I mean? Like, he would not say a word.”

Matt said that while Kayumi did not get bullied regularly, he was sometimes a target.

“He wasn’t really that violent, but if someone would say something to him, like disrespecting him or something, he wasn’t afraid to say something back,” Matt said.

Matt and Lombardi recalled that Kayumi was involved in at least one physical altercation at school. The two former classmates did not witness the fight and could not recall who else was involved or who instigated it. They said they remember the altercation because physical violence at their high school was “very uncommon.” A representative for the school declined to comment on Kayumi’s student records.

Lombardi, 19, said he used to sit next to Kayumi on the bus to and from school nearly every day during their sophomore year. He described Kayumi as “independent” but not someone who shied away from conversation.

“He didn’t have any telling signs if we’re comparing it to what just happened,” Lombardi said. “He would not in any aspect whatsoever have been my first guess.”

Lombardi said that although they spoke often during their sophomore year, Kayumi was not on his list of people to say goodbye to at the end of high school.

It is not immediately clear what Kayumi has been doing since leaving high school and starting community college. A college spokesperson said Kayumi withdrew from the school by March 9.

Kayumi’s mother filed a missing person report for her son on March 7, saying she last saw her son at around 10:30 a.m. — two hours before his arrest, according to the complaint.

“If he’s going to be five minutes late, he calls,” Kayumi’s father told The New York Times in an interview.

Teens allegedly drove to New York with explosive materials

Balat grew up 4 miles south of Kayumi on a similarly tree-lined street in Langhorne, Pennsylvania.

His father, Selahattin Balat, immigrated to the U.S. from Turkey and became a citizen in 2017, according to a lawsuit he filed against the Department of Homeland Security over his citizenship application in 2015.

On Thursday, a man who identified himself as Balat’s father answered the front door of the family’s palatial home and declined to comment.

Balat is a senior at Neshaminy High School in Langhorne, Pennsylvania, according to a school spokesperson. The spokesperson confirmed to NBC News that Balat has been finishing his senior year remotely since September.

When asked for comment on last week’s incident, the Neshaminy School District shared two letters from the district’s superintendent to parents and staff, including one that said there was no information indicating concerns about Balat related to the school.

The New York Times and The Philadelphia Inquirer reported that Balat had been selling designer sneakers at a markup, sometimes for hundreds of dollars, out of a Wawa parking lot since he was 13 years old. He was also selling products on Facebook Marketplace as recently as 19 days before the incident in New York.

One of Balat’s neighbors, who asked that NBC News not publish her name due to fears of retaliation, described the family as “loving,” “open,” “welcoming” and “kindhearted.”

She said she didn’t speak with Balat much over the last few years, but that he seemed like a “typical kid.” Balat shoveled her driveway during a snowstorm a few years ago.

“It doesn’t surprise me because this is the world we’re in right now,” she said. “But it does surprise me that it’s right here.”

On March 2, Balat purchased a fireworks fuse from Phantom Fireworks in Langhorne. Surveillance video shared with NBC News shows him arriving at the company’s Penndel location at around 12:15 p.m., registering his identification with an employee — a step the company requires of all customers — and buying a single 20-foot roll of green safety fuse with cash.

Phantom Fireworks Executive Vice President Alan Zoldan said the company searched its records for the suspects’ names after the attempted bombing and found a match for Balat, which led employees to the roughly 10-minute store visit captured on video. Zoldan also showed NBC News a copy of a subpoena he said federal prosecutors sent to the company.

Five days later, prosecutors say, Kayumi and Balat drove from Pennsylvania to New York City in a black Honda registered to one of Balat’s family members, crossing the George Washington Bridge to Manhattan at around 11:36 a.m. ET.

At about 12:15 p.m. ET, Balat threw an explosive device toward the area where protesters gathered at an anti-Islam rally outside the mayor’s official residence on the Upper East Side, according to officials. The rally was led by conservative provocateur Jake Lang and attracted fewer than two dozen protesters and more than 120 counterprotesters, according to authorities.

Shortly afterward, Kayumi handed off a second explosive device to Balat, who dropped the device near police officers before the pair was arrested, according to the complaint.

After waiving his Miranda rights, the complaint says, Kayumi said he “was affiliated with ISIS; watched ISIS propaganda on his phone; and was partly inspired to carry out his actions that day by ISIS.”

Investigators recovered a notebook from the car Balat and Kayumi drove, which contained handwritten notes that reference “materials that could be used to build explosive devices,” according to the complaint.

Authorities also removed “explosive residue” from a Pennsylvania storage unit believed to be connected to the incident. A senior law enforcement official briefed on the investigation told NBC News that local police detonated some of the components out of caution late Monday.

Investigators are still trying to determine how Balat and Kayumi met and what led them to allegedly plan the attack.

For Matt, it’s been difficult trying to reconcile the classmate he remembers and the allegations against him.

“We just thought he was a normal kid, like all of us, pretty much,” Matt said. “We were all shocked.”