Investigators were looking into the similarities between the explosion and others that have taken place in the city over the last four years, Police Commissioner Ray Kelly said. The bomb went off around the same time of day as an explosion at the British consulate in May 2005, another at the Mexican consulate in October 2007 and one at the Times Square military recruiting station in March 2008.
In the previous bombings, a bicyclist was seen in the area prior to the explosions. No witnesses came forward immediately Monday, and police still have to see what, if any, security camera footage is available, Kelly said.
"We don't know the motive. Obviously it is a cause for concern, but we're going to do an in-depth investigation," he said.
Kelly said the explosive appears to have been placed on the seat of the bench, but didn't know what kind of container it was in. He said investigators would examine the remains to determine what kind of explosive it was. He was it was possible it was some kind of firework.
Police also were looking at whether the Starbucks -- at 92nd Street and Third Avenue, a few blocks from the Guggenheim Museum -- was the target.
Residents living above the coffee shop were evacuated for a time but were allowed to return to their apartments later in the morning.
One of them, Jordan Kovnot, a 26-year-old law school student, told the Daily News, "I heard a giant noise -- a big, giant noise, like a crash -- and there was a flash."
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