Glendon Scott Crawford, 49, and Eric J. Feight, 54, are said to have spent several months building a complicated X-ray device that would emit deadly amounts of radiation and could be detonated remotely, FBI says.
The duo allegedly planned to hide their weapon in a truck and FBI experts said it would have been "functional" and "lethal."
The FBI also cited Crawford as saying the potential targets were "a political figure" and a Muslim organization. Sources familiar with the investigation identified the "political figure" as Barack Obama.
"Obama's policies caused this," Crawford allegedly wrote texed after the Boston marathon bombing.
The FBI has been keeping an eye on Crawford since last spring when he allegedly walked into a synagogue and inquired about technology that could kill "Israel's enemies while they slept." The synagogue called the police, and within six weeks the FBI had a source secretly recording meetings with Crawford