BOSTON -- Bombing suspect Dzhokhar Tsarnaev and his older brother Tamerlan initially planned the attack for the upcoming July Fourth holiday but changed their minds shortly before the Boston Marathon because the race was an "ideal" target, a federal law enforcement source said Thursday.
The assembly of two pressure-cooker bombs that exploded at the marathon April 15 went faster than the two brothers expected and also weighed on their decision to change their plans, the source said.
Information about the switch in targets came from several investigative threads and details gleaned from hospital interviews with Dzhokhar Tsarnaev two weeks ago before he was read his Miranda rights and stopped talking to authorities, the source said.
The 19-year-old student at the University of Massachusetts Dartmouth told FBI agents he and Tamerlan Tsarnaev saw Patriots Day and the symbolism attached to it as an ideal time to set off the bombs, the source said. Turning the attack into a suicide bombing was one "possibility" the brothers considered, the source said.
Dzhokhar Tsarnaev told investigators he and his brother built their pressure-cooker bombs at Tamerlan Tsarnaev's home, according to the source. Once they settled on a day for the attack, they scouted the marathon course before deciding that the finish line -- packed with onlookers and a large news-media presence -- was where they would set off the bombs, the source said.
Investigators also continued to search two laptops belonging to the Tsarnaev brothers for any evidence the pair had help planning the attacks, according to the law enforcement source. And Thursday night, Tamerlan Tsarnaev's body was claimed, said Terell Harris, a spokesman for the Boston medical examiner's office.
Harris would not say who claimed the body or whether it was removed from the medical examiner's headquarters.
Tuesday, attorneys for Katherine Russell, Tamerlan Tsarnaev's wife, said her wish was that his remains be released to his family "and we will communicate her wishes to the proper authorities."
Tamerlan Tsarnaev died after an early-morning shootout four days after the attacks following a high-speed chase from the Cambridge campus of the Massachusetts Institute of Technology to the Boston suburb of Watertown.
His computer, along with a laptop owned by Dzhokhar, were recovered in the days after the bombing.
Investigators are poring over the two computers' emails, pictures, contacts and any other data that could expand the probe, including whether Islamic leaders in Russia radicalized Tamerlan Tsarnaev, the source said.
Dzhokhar told investigators he and his brother had listened to online sermons of Anwar al-Awlaki, the American-born radical who was killed in 2011 U.S. airstrike in Yemen.