Feds test bomb remnants of New York blast that injured 29

NEW YORK -- The bomb that rocked a New York City neighborhood known for its arts scene and gay community contained residue of an explosive often used for target practice that can be picked up in many sporting-goods stores, a federal law-enforcement official said Sunday, as authorities tried to unravel who planted the device and why.

The discovery of Tannerite in materials recovered from the Saturday-night explosion that injured 29 people may be important as authorities probe whether the blast was connected to an unexploded pressure-cooker device found by state troopers blocks away, as well as a pipe-bomb blast in a New Jersey shore town earlier in the day.

Gov. Andrew Cuomo, touring the site of the blast in Manhattan's Chelsea neighborhood, said there didn't appear to be a link to international terrorism. He said the second device appeared "similar in design" to the first but did not provide details.

"We're going to be very careful and patient to get to the full truth here," New York's mayor, Bill de Blasio, a Democrat, said Sunday. "We have more work to do to be able to say what kind of motivation was behind this. Was it a political motivation? A personal motivation? What was it? We do not know that yet."

Cellphones 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 on condition of anonymity because the official was not authorized to comment on an ongoing investigation.

A view of a mangled construction toolbox Sunday at the site of an explosion Saturday night in the Chelsea neighborhood of New York. Twenty-nine people were injured in the blast.Justin Lane ~ EPA via AP

Authorities said the Manhattan bombing and the blast 11 hours earlier at the site of a 5K race to benefit Marines and sailors in Seaside Park, New Jersey, didn't appear to be connected, though they weren't ruling anything out. The New Jersey race was canceled, and no one was injured.

Officials haven't revealed details about the makeup of the pressure-cooker device, except to say it had wires and a cellphone attached.

Technicians in Quantico, Virginia, were examining evidence from the Manhattan bombing, described by witnesses as a deafening blast that shattered storefront windows and injured bystanders with shrapnel in the mostly residential neighborhood on the city's west side. All of the injured people were released from the hospital by Sunday.

The explosion left many rattled in a city that had marked the 15th anniversary of the 9/11 terrorist attacks a week earlier, and a United Nations meeting was set for today to address Syrian refugee crisis.

"People didn't know what was going on, and that's what was scary," said Anthony Zayas, an actor who was in the Chelsea neighborhood Saturday night when the bomb went off. "You didn't know if it was coming from the subway beneath you; you didn't know if there were other bombs; you didn't know where to go."

Tannerite, often used in target practice to mark a shot with a cloud of smoke and small explosion, is legal to purchase and can be found in many sporting-goods stores. Experts said a large amount would be required to create a blast such as the one Saturday night, as well as an accelerant or other ignitor.

Police and federal spokespeople wouldn't comment on the presence of explosive material found at the scene.

The bomb in Manhattan appeared to have been placed near a large Dumpster in front of a building undergoing construction, said another law-enforcement official, speaking on condition of anonymity to discuss the ongoing investigation.

The second device, described by the same official as a pressure cooker with wires and a cellphone attached to it, was removed early Sunday by a bomb squad robot and New York City police were preparing to blow it up in a controlled explosion later in the day, authorities said.

Homemade pressure cooker bombs were used in the Boston Marathon attacks in 2013 that killed three people and injured more than 260.

Officials solicited tips from the public, telling reporters at a news conference in the New York Police Department's headquarters that they didn't know who set off the bomb or why.

An additional 1,000 state troopers and members of the National Guard were placed at transit hubs and other points throughout New York City and extra police officials were patrolling Manhattan, officials said. 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.

Meanwhile, a law enforcement official said federal investigators had discounted a claim of responsibility on the social blogging service Tumblr. Investigators looked into it and didn't consider it relevant to the case, said the official who spoke on condition of anonymity to discuss an ongoing investigation.

Anthony Stanhope, 40, a songwriter who lives a block away from the bombing, said he needed more answers before he could feel safe.

"I think it's terrorism -- I don't know what kind. It's some kind of fanaticism, I don't know exactly what it is," he said. "But somebody has an agenda to cause trouble in this country."