The Manhattan explosion that injured 29 people had residents on high alert Sunday night when police questioned several people after a car stop in Brooklyn as they work to determine whether the series of incidents over the weekend are connected, The Associated Press reported.
First, a pipe bomb blast rattled a New Jersey shore town on Saturday. Later that night, an explosion rocked a bustling New York City neighborhood and an unexploded pressure-cooker device was found blocks away. Overnight, another device was discovered at a New Jersey train station.
On Sunday night, FBI agents stopped "a vehicle of interest in the investigation" of the Manhattan explosion, according to FBI spokeswoman Kelly Langmesser
She wouldn't provide further details, but a government official and a law enforcement official who were briefed on the investigation told the AP that five people in the car were being questioned at an FBI building in lower Manhattan.
The officials spoke on condition of anonymity because they were not authorized to talk about the ongoing investigation.
No one has been charged with any crime, and the investigation is continuing, Langmesser said.
Gov. Andrew Cuomo, touring the site of Saturday's blast that injured 29 people in Manhattan's Chelsea neighborhood, said there didn't appear to be any link to international terrorism. He said the second device appeared "similar in design" to the first, but did not provide details.
On Sunday, a federal law enforcement official said the Chelsea bomb contained a residue of Tannerite, an explosive often used for target practice that can be picked up in many sporting goods stores. The discovery of Tannerite may be important as authorities probe whether the three incidents are connected.
Cell phones were discovered at the site of both bombings, but no Tannerite residue was identified in the New Jersey bomb remnants, in which a black powder was detected, said the official, who spoke to the AP on condition of anonymity because the official was not authorized to comment on an ongoing investigation.
Authorities said the Manhattan bombing and New Jersey pipe bomb didn't appear to be connected, though they weren't ruling anything out. The New Jersey race was cancelled and no one was injured.
Late Sunday, more suspicious devices were found near a train station in Elizabeth, New Jersey. Elizabeth Mayor Christian Bollwage said the devices were found in a bag in a trash can by two men who reported seeing wires and a pipe coming out of the package. There turned out to be five devices in the bag. One of the devices exploded as a bomb squad used a robot to try to disarm it. No injuries were reported.
There was no immediate word on whether the devices were similar to those in nearby Seaside Park or New York City.
Officials haven't revealed any details about the makeup of the pressure-cooker device, except to say it had wires and a cellphone attached to it. On Sunday night, police blew up the device, rendering it safe. A forensic examination of the device will be sent to the FBI Laboratory at Quantico, Virginia, police said.
Homemade pressure cooker bombs were used in the Boston Marathon attacks in 2013 that killed three people and injured more than 260.
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.
The Chelsea explosion left many rattled in a city that had marked the 15th anniversary of the 9/11 terrorist attacks only a week earlier and where a United Nations meeting to address the refugee crisis in Syria was scheduled on Monday.
Witnesses described a deafening blast that shattered storefront windows and injured bystanders with shrapnel in the mostly residential neighborhood on the city's west side.
As authorities tried to unravel who planted the device and why, one New Yorker, Anthony Stanhope, 40, knew exactly what had just happened.
"I was sitting in my apartment, and all of a sudden I heard a big boom, and I thought to myself wait a minute, it can't be thundering and lightning at this hour, and then all of a sudden car horns went off, and I thought oh my god this isn't lightning, this is too loud - this is a bomb," said Stanhope.