Footage from a surveillance camera video released Thursday afternoon shows a biker who might have been involved in the Big Apple bombing and whom authorities are seeking for questioning in the case.
New York City police on Thursday released the video, in which the bicyclist can be seen riding in the dark in the vicinity of the Times Square military recruiting center minutes before the blast.
The footage from a private security camera shows the cyclist riding up to the military station where a small bomb was detonated before dawn. The biker is seen getting off the 10-speed bike at 3:40 a.m. Thursday; the blast occurs three minutes later. It is followed by a brief flash and a cloud of white smoke.
Police say they later found the bike in the trash.
Earlier Thursday, police in Washington, D.C. were investigating letters mentioning the Times Square bombing that were mailed to Capitol Hill offices, however, sources have told FOX News that investigators have found no connection to the attack.
New York City Mayor Michael Bloomberg said the explosion that shook Times Square and disrupted transit appears to have deliberately targeted the military recruiting center where it went off.
Bloomberg lambasted the perpetrator for apparently going after the armed forces.
"The fact that this appears deliberately directed at the recruiting station insults every one of our brave men and women around the world," the mayor said in a Thursday morning news conference.
Authorities in New York City were looking for the culprit who set off the rudimentary explosive device. A witness described a hooded man on a bicycle wearing a backpack and acting suspiciously just before the blast at the recruiting station.
New York City Police Commissioner Ray Kelly said an ammunition box was found at the scene.
"This was not a particularly sophisticated device," he told reporters.
Kelly said police were talking to the witness who was in the area shortly before the 3:45 a.m. explosion. The witness described a male bicyclist wearing a hood, dark clothing and a backpack and acting strangely — but said didn't see the man's face, according to Kelly.
Bloomberg said no one has come forward to report seeing a suspect plant a bomb, and no one so far has spoken of witnessing the device going off. Authorities have been reviewing all available security camera footage, according to the mayor.
The blast occurred when an explosive device detonated, causing minor damage to an empty recruiting station in Times Square — an area that is heavily populated with New York City tourists. Hotel guests were shaken by the force in their rooms high above the scene. No one was injured, but the station's glass entryway was shattered.
The Homeland Security department said there was no sign of an "imminent threat" to the United States in the blast, according to Reuters.
The agency also announced Thursday that the FBI would be joining the probe into what caused the explosion.
In October, two small explosive devices were tossed over a fence at the Mexican Consulate on Manhattan's East Side, shattering some windows; police said they believed someone on a bicycle threw the devices. At the time, police said they were investigating whether it was connected to a similar incident at the British consulate on May 5, 2005.
Bloomberg had harsh words for the person or people who planted the explosives.
"Whoever the coward was that committed this disgraceful act on our city will be found and prosecuted to the full extent of the law," he said. "We will not tolerate such attacks. .... People are going about their business. They are not intimidated."
Army Capt. Charlie Jaquillard, who is the commander of Army recruiting in Manhattan, said no one was inside the station at the time — where the Marines, Air Force and Navy also recruit.
"If it is something that's directed toward American troops than it's something that's taken very seriously and is pretty unfortunate," he said.
The explosion prompted a huge police response that disrupted transit at the "crossroads of the world."
It left a gaping hole in the front window and shattered a glass door, twisting and blackening the metal frame of the building, which is on a traffic island.
Police said investigators would have to examine the evidence to determine exactly what kind of device was used.
The recruiting center has drawn sporadic protests for many years, including in October 2005, when a group who call themselves the Granny Peace Brigade rallied there against the Iraq war. Eighteen activists, most of them grandmothers in their 80s and 90s, were later acquitted of disorderly conduct.
Police cars and yellow tape initially blocked drivers from entering one of the world's busiest crossroads, though some traffic was allowed through around the start of rush hour.
Witnesses staying at a Marriott hotel four blocks away said they could feel the building shake with the blast.
"I was up on the 44th floor and I could feel it. It was a big bang," said Darla Peck, 25, of Portland, Oregon.
"It shook the building. I thought it could have been thunder, but I looked down and there was a massive plume of smoke so I knew it was an explosion," said Terry Leighton, 48, of London, who was staying on the 21st floor of the Marriot.
Members of the police department's bomb squad and fire officials gathered outside the station in the early morning darkness, and police cars and yellow tape blocked drivers — most of them behind the wheels of taxicabs — from entering one of the world's busiest crossroads.
Though subway cars passed through the Times Square station without stopping in the early hours of the investigation, normal service was soon restored, with some delays.
The recruiting station was renovated in 1999 to better fit into the flashy ambiance of Times Square, using neon tubing to give the glass and steel office a patriotic American flag motif. For a half century, the station was the armed forces' busiest recruiting center. It has set national records for enlistment, averaging about 10,000 volunteers a year.
Police said it was too early to say if the blast may have been related to the two other minor explosions in the city.
In October, two small explosive devices were tossed over a fence at the Mexican consulate, shattering three windows but causing no injuries. No threats had been made against the consulate, and no one took responsibility for the explosion, police said.
Aside from the attack on the Mexican consulate, another happened on May 5, 2005, at the British consulate. In that incident, the explosions took place in the early morning hours, when Britons were going to the polls in an election that returned Prime Minister Tony Blair to power.
In both cases, the instruments were fake grenades sometimes sold as novelty items. They were packed with black power and detonated with fuses, but incapable of causing serious harm, police said.
The Associated Press contributed to this report.