BOSTON — The twin bombs that exploded near the finish line of the Boston Marathon were likely detonated with long-range remote controls, like the kind found in children's toys, according to an "intelligence bulletin" sent to police agencies.
The bulletin was issued Wednesday by the FBI and the U.S. Department of Homeland Security to warn law enforcement agencies of the potential threat of such toys. It was shared with Newsday by a federal law enforcement source involved in the bombing investigation.
Federal authorities accused two men, Dzhokhar Tsarnaev, 19, and his brother, Tamerlan, 26, of placing backpacks containing the bombs at the marathon finish line and detonating them after walking a safe distance away.
The bombers' possible use of remote control devices and the design of the pressure-cooker bombs — they were packed with nails and BBs — suggests that the planning of the attack was more sophisticated than investigators initially thought, Newsday reported, citing the unnamed federal official.
The bulletin states that: "Based on preliminary analysis of recovered evidence, each device likely incorporated an electrical fusing system using components from remote control toy cars such as a transmitter and receiver pair operating at 2.4 GHz, an electronic speed control used as the switch mechanism and sub-C rechargeable battery packs at the power source."
A similar device was found in the failed May 2010 bombing of Times Square, the official said.
While explosives experts are stateside trying to answer the how of the marathon bombings, FBI agents are in the Dagestan republic of Russia — where the brothers have roots — trying to answer the why. Together with Russian intelligence officers, FBI agents are interviewing Zubeidat Tsarnaeva and Anzor Tsarnaev, the parents of the brothers.
Speaking in Brussels on Wednesday, U.S. Secretary of State John Kerry said Tamerlan Tsarnaev went abroad "and he came back with a willingness to kill people."
Meanwhile, no one has yet come forward to claim the body of Tamerlan Tsarnaev from the Massachusetts Office of the Chief Medical Examiner, a spokesman for the office said Wednesday.
Zubeidat Tsarnaeva, the brothers' mother, told CNN on Wednesday: "If they are going to kill him, I don't care. My oldest one is killed, so I don't care. I don't care if my youngest one is going to be killed today. I want the world to hear this. And I don't care if I am going to get killed, too. And I will say 'Allahu akbar' (God is great)."