Boston suspects planned Independence Day bombing, say authorities Tamerlan and Dzhokhar Tsarnaev at the scene of the Boston Marathon bombing last month, in a picture released by the FBI. The two brothers suspected of carrying out the attack on the Boston Marathon had originally planned to set off their bombs on US Independence Day, according to law enforcement officials. Tamerlan and Dzhokhar Tsarnaev brought forward the date of their attack from 4 July because they completed building bombs more quickly then they originally anticipated, according to officials quoted in multiple media reports. Police say the brothers detonated two bombs made with pressure-cookers in the 15 April attack on the Boston Marathon that killed three people and wounded 264. The New York Times, NBC News and Reuters all reported news of the 4 July plan, quoting officials briefed on the interrogation of the surviving suspect, 19-year-old Dzhokhar Tsarnaev. Tamerlan Tsarnaev, 26, was killed in a shootout with police in Watertown, Massachusetts, on 19 April. His brother was wounded in the shootout and captured later that day. Dzhokhar Tsarnaev has been charged with crimes in connection with the bombing that could carry the death penalty if convicted and is being held at a prison medical facility in Devens, Massachusetts. The remains of Tamerlan Tsarnaev were claimed on behalf of his family on Thursday. His body had been kept at a Boston facility for more than a week. Terrel Harris, a spokesman for the Office of the Chief Medical Examiner of Massachusetts, said a funeral services company retained by the family had claimed the body. Harris declined to provide details including the cause of death or where the body had been taken. On Tuesday, Tamerlan Tsarnaev's widow, Katherine Russell, said through an attorney that she did not wish to claim his remains and wished them to be released to the Tsarnaev family. Investigators have questioned Russell as they seek clues about how the ethnic Chechen brothers allegedly built the two bombs used in the attack and whether they had help. The suspects' parents previously lived in Cambridge, Massachusetts, but have since returned to Russia. Other relatives remain in the US, including an uncle, Ruslan Tsarni of Montgomery Village, Maryland, who has been seen in Rhode Island in recent days. Officials said on Thursday that three men who had been charged with interfering with the investigation of the bombing were in custody at a jail in Middleton, Massachusetts, a small town about 20 miles north of Boston. The three 19-year-olds - Azamat Tazhayakov, Dias Kadyrbayev and Robel Phillipos - had been transported to the Essex County correctional facility in Middleton on Wednesday after they were charged in Boston. Authorities have described them as college friends of Dzhokhar Tsarnaev. On Thursday a Republican senator, Chuck Grassley, asked the Obama administration to explain how one of the students entered the US without a valid student visa. In a three-page letter to the homeland security secretary, Janet Napolitano, Grassley asked for additional details about the student visa applications for Tazhayakov and Kadyrbayev, college roommates from Kazakhstan. Tazhayakov was a student at the University of Massachusetts Dartmouth when he left the country in December. In early January his student visa status was terminated because he was academically dismissed by the university. Grassley asked how Tazhayakov was allowed to re-enter the US in January. Tazhayakov and Kadyrbayev have been charged with conspiring to obstruct justice. The third arrested student, Robel Phillipos, a US citizen, was charged with willfully making materially false statements to federal law enforcement officials during a terrorism investigation. Lawyers for the Kazakh students said their clients had nothing to do with the bombing and were just as shocked by it as everyone else. Phillipos's lawyer said the only allegation against him was that "he made a misrepresentation." Reuters and Associated Press contributed to this report.