The two brothers suspected of carrying out last week's deadly Boston Marathon bombing decided, after the FBI released photos of them, to drive to Manhattan and detonate more explosives in Times Square, New York City officials said on Thursday.Their plan unraveled when they realized a Mercedes sport utility vehicle they had hijacked on April 18, three days after the Boston bombing, did not have enough gasoline for the journey, said New York Police Commissioner Ray Kelly.New York has been on heightened alert since the Sept. 11, plane hijackings in 2001 destroyed the World Trade Center and officials said the plan by the Boston bombing suspects, ethnic Chechens Tamerlan and Dzhokhar Tsarnaev, showed America's most populous city remained a magnet for attackers."Questioning of Dzhokhar revealed that he and his brother decided spontaneously on Times Square as a target," Kelly told a news conference with New York Mayor Michael Bloomberg. "They would drive to Times Square that same night."That plan, however, fell apart when they realized that the vehicle that they hijacked was low on gas and ordered the driver to stop at a nearby gas station," Kelly said.At the time, the men still had six explosive devices, including a pressure-cooker bomb of the type used at the marathon and six pipe bombs, he said.When they stopped to refuel, the driver of the vehicle escaped, Kelly said. The driver alerted authorities and set off a late-night chase and shootout in suburban Watertown, where police say the suspects threw improvised explosives at officers. Hours earlier, the brothers had shot and killed a Massachusetts Institute of Technology campus police officer in Cambridge, authorities said.Meanwhile, the brothers' parents continued to claim their sons' innoence. The brothers' father said he planned to travel to the United States from Russia to bury his older son, Tamerlan Tsarnaev."I am going to the United States. I want to say that I am going there to see my son, to bury the older one. I don't have any bad intentions. I don't plan to blow up anything," Anzor Tsarnaev told reporters in Makhachkala, the capital of Russia's Dagestan region.Massachusetts Governor Deval Patrick said investigators might be interested in speaking to the parents."There are a lot of questions unanswered about the whys and the hows, and anybody who may be able to shed some light on that is of interest to law enforcement," Patrick said.Anzor Tsarnaev's former wife, Zubeidat Tsarnaeva, angrily denied that her son had any role in the attack and criticized police for shooting him while apprehending him.Tsarnaeva does not plan to accompany her former husband on his trip. One factor that may have influenced her decision is an outstanding arrest warrant for her in Massachusetts.A warrant for Zubeidat Tsarnaeva's arrest was issued on Oct. 25 after she failed to make a court appearance on shoplifting-related charges, according to Natick District Court Clerk Brian Kearney.