US authorities interview Boston bombing suspects' parents in Russia The father of the Boston Marathon bombing suspects has been interviewed by Russian and American authorities and will make his way to the United States along with his ex-wife as early as Thursday while more details emerge about the brothers' recent activities in the U.S., including word of where the deadly explosives may have been purchased and that the family relied on welfare for at least some of their time here. A U.S. Embassy official said the Americans traveled from Moscow to the predominantly Muslim province of Dagestan "because the investigation is ongoing, it's not over." The official, who spoke on condition of anonymity because he was not authorized to speak to the media, said Wednesday that the team is working with the Russian security services, the FSB. The boys' father, Anzor Tsarnaev, told Fox News Wednesday that FBI and FSB authorities had visited him, adding that FBI officials were polite while asking him questions. Tsarnaev said he still believes his sons were innocent, that they were somehow framed in the bombings and that Tamerlan, who was shot and killed in a gunfight with law enforcement, was apprehended alive. He also denied that Tamerlan was associated with extremists. Tsarnaev plans to travel to the United States as early as Thursday with the boys" mother, he told Fox News. The family has said it wants to bring Tamerlan's body back to Russia. Zubeidat Tsarnaeva, the mother of Tamerlan and Dzhokhar Tsarnaev, was to be interviewed Wednesday in the FSB building in Makhachkala, the capital of Dagestan. The official said one positive development from the Boston tragedy might be closer cooperation with the Russian government on security issues. Zubeidat Tsarnaeva, who was arrested in the United States in June on charges of shoplifting, has told The Associated Press that her son Tamerlan greatly enjoyed his time with her relatives during a trip to his ancestral homeland in southern Russia last year. But Tsarnaeva said he never traveled to her native village in a mountainous region of Dagestan, which is a hotbed of an ultraconservative strain of Islam known as Wahabbism. Wahabbism was introduced to the Caucasus in the 1990s by preachers and teachers from Saudi Arabia. Meanwhile, new information surfaced Wednesday about the older of the two brothers, as the manager of a New Hampshire fireworks store said 26-year-old Tamerlan Tsarnaev was seen buying two mortar kits at the store in February. April Walton, of Phantom Fireworks, says Tamerlan bought two "Lock and Load" reloadable mortar kits with 24 shells each. Company Vice President William Weimer says FBI agents visited the Seabrook store on Friday, interviewed staff and checked its computers. He says the amount of gunpowder that could be harvested from the kits would not have been enough to detonate the Boston bombs. Walton says Tsarnaev paid $200 cash, but scanned his driver's license into the company's computer system as required by store policy. Walton says the employee who handled the sale described it as a routine transaction. Faisal Shahzad, who has pleaded guilty for his attempted Times Square bombing on May 1, 2010, also purchased fireworks used to build his failed car bomb from the same company. Shahzad bought consumer-grade fireworks from Phantom Fireworks' showroom in Matamoras, Pa. "We were just shocked," Weimer told the New York Daily News from the company's store in Seabrook, N.H. "After our Times Square experience, we said, 'It can't happen twice.'" Tamerlan Tsarnaev was also living on taxpayer-funded state welfare benefits while he was "delving deep" into the world of radical anti-American Islamism, the Boston Herald reports. State officials confirmed to the newspaper late Tuesday that Tsarnaev, who was killed during a gun battle with police on Friday, was receiving benefits along with his wife, Katherine Russell Tsarnaev, and their 3-year-old daughter. The state's Executive Office of Health and Human Services said those benefits ended in 2012 when the couple stopped meeting income eligibility limits. Russell Tsarnaev's attorney has claimed Katherine - who had converted to Islam - was working up to 80 hours a week as a home health aide while Tsarnaev stayed at home, the newspaper reports. "The brothers were not receiving transitional assistance benefits at the time of the incident and have not received any transitional assistance benefits this year," Massachusetts Health and Human Services communication director Alec Loftus told the newspaper in a statement. "The Tsarnaevs" parents are former recipients of transitional assistance benefits, and both Dzhokhar and Tamerlan Tsarnaev received benefits through their parents when they were younger. Separately, Tamerlan and his family received benefits until 2012, when the family became ineligible based on their income. Meanwhile, the body of Tamerlan Tsarnaev has not been claimed by either his parents or his 24-year-old widow. A spokesman for the Massachusetts Office of the Chief Medical Examiner wouldn't comment on whether Tsarnaev's wife has asked to claim the body. Lawyers for Russell Tsarnaev have said she "is doing everything she can to assist with the investigation," and is mourning the victims of the bombings. The area near the Boston Marathon finish line also reopened to the general public early Wednesday. Traffic was allowed to flow all the way down Boylston Street for the first time since two explosions on April 15 killed three spectators and hospitalized 260 others. Click for more from the Boston Herald.