In this May 4, 2013, police mug provided by the Orange County Corrections Department in Orlando, Fla., shows Ibragim Todashev after his arrest for aggravated battery in Orlando. Todashev, who was being questioned in Orlando by authorities in the Boston bombing probe, was fatally shot Wednesday, May 22, 2013, when he initiated a violent confrontation, FBI officials said. (AP Photo/Orange County Corrections Department)
During the execution of a search warrant, members of the Joint Federal Haz-Mat Team, FBI, and local law enforcement gather in front of the Osmun Apartments near the intersection of First Avenue and Oak Street in Browne's Addition on Saturday, May 18, 2013 in Spokane, Wash. The search warrant is in connection with ricin-laced letters intercepted at a Post Office facility in Spokane earlier in the week. (Associated Press)
During the execution of a search warrant, members of the Joint Federal Haz-Mat Team, FBI, and local law enforcement gather in front of the Osmun Apartments near the intersection of First Avenue and Oak Street in Browne's Addition on Saturday, May 18, 2013 in Spokane, Wash. The search warrant is in connection with ricin-laced letters intercepted at a Post Office facility in Spokane earlier in the week. (Associated Press)
** FILE ** FBI agents walk along Norfolk Street in Cambridge, Mass., on April 19, 2013. (Associated Press)
**FILE** Tamerlan Tsarnaev smiles after accepting the trophy for winning the 2010 New England Golden Gloves Championship in Lowell, Mass., on Feb. 17, 2010. The 26-year-old boxer, who had been known to the FBI as Suspect No. 1 in the Boston Marathon explosions and was seen in surveillance footage in a black baseball cap, was killed on April 19, 2013, officials said. (Associated Press/The Lowell Sun)
In this May 4, 2013, police mug provided by the Orange County Corrections Department in Orlando, Fla., shows Ibragim Todashev after his arrest for aggravated battery in Orlando. Todashev, who was being questioned in Orlando by authorities in the Boston bombing probe, was fatally shot Wednesday, May 22, 2013, when he initiated a violent confrontation, FBI officials said. (AP Photo/Orange County Corrections Department)
**FILE** Tamerlan Tsarnaev smiles after accepting the trophy for winning the 2010 New England Golden Gloves Championship in Lowell, Mass., on Feb. 17, 2010. The 26-year-old boxer, who had been known to the FBI as Suspect No. 1 in the Boston Marathon explosions and was seen in surveillance footage in a black baseball cap, was killed on April 19, 2013, officials said. (Associated Press/The Lowell Sun)
**FILE** FBI Director Robert S. Mueller III testifies on May 16, 2012, on Capitol Hill before the Senate Judiciary Committee. (Associated Press)
Members of the Joint Federal Haz-Mat Team, FBI and local law enforcement gather in front of the Osmun Apartments in Spokane, Wash., to execute a search warrant in connection with ricin-laced letters intercepted at a post office in the city's downtown earlier in the week. (AP Photo/The Spokesman-Review, Colin Mulvany)
