NEW YORK (NYTimes) - A bomb that injured 29 people in the Chelsea neighbourhood of Manhattan, and another that failed to detonate, were filled with shrapnel and made with pressure cookers, flip phones and Christmas lights that set off a powerful explosive compound, law enforcement officials said.
Both bombs appeared designed to create maximum chaos and fatalities - they also provided a trove of clues even as any suspect remained unnervingly at large.
A top law enforcement official said pressure cookers were filled with "fragmentation materials".
The bomb that exploded was filled with small bearings or metal BBs. A second device that did not explode appeared to be filled with the same material, the official said.
Late Sunday (Sept 18), two senior law enforcement officials said they had identified a "person of interest" in the bombing, though they did not refer to that person as a suspect.
Senior law enforcement officials also said that they were increasingly focused on the possibility that the attack was connected to a bombing that took place 11 hours earlier in New Jersey, but the authorities still needed to compare all the bombs before drawing any conclusions.
There, three pipe bombs were tied together, placed in a trash can and also employed by a flip cellphone as a timing mechanism, according to officials. Only one of the three pipe bombs detonated and no one was injured. Officials said the explosive in that device appeared to be black powder.
Officials said they did not know of any motive - political or social - for any of the attacks. Early Sunday, Governor Andrew M. Cuomo said "there is no evidence of an international terrorism connection with this incident", noting that no international terrorist group had claimed responsibility.
The search for the person or people behind the attack in New York took on added urgency as President Barack Obama and leaders from around the world travel to New York for the annual UN General Assembly this week.
Mr Cuomo said he was ordering an additional 1,000 New York State Police officers and National Guard members to be dispatched to major commuter hubs, and Mayor Bill de Blasio said New Yorkers should expect to see a heightened police presence throughout the city, including additional patrols by the city's heavily armed counter-terrorism units.