(CBS/AP) BOSTON - A Massachusetts man charged with plotting to fly remote-controlled model planes packed with explosives into the Pentagon and U.S. Capitol plans to plead guilty to two charges, according to court documents filed by prosecutors and defense attorneys.
Rezwan Ferdaus, a Muslim-American with a physics degree from Boston's Northeastern University, was arrested in September after federal employees posing as al Qaeda members delivered what he believed was 24 pounds of C-4 explosives.
In the documents, prosecutors and Ferdaus' lawyers say they have entered a plea agreement and requested a hearing so Ferdaus can change his plea.
The documents say Ferdaus will plead guilty to attempting to provide material support to terrorists and attempting to damage and destroy federal buildings by means of an explosive. Prosecutors and defense attorneys have agreed to request a 17-year sentence.
Federal officials said the public was never in danger from the explosives.
FBI special agent Bradley Davis, testifying for prosecutors in November, said Ferdaus asked undercover FBI employees he believed were al Qaeda members to get him C-4 explosives, AK-47 assault rifles and grenades so he could carry out the attacks. Davis said Ferdaus also showed the undercover employees a cellphone he had fashioned into a detonator. Davis said FBI bomb technicians analyzed the device and "came to the conclusion that it could actually be used" to detonate explosives.
"The device would function to provide an electrical impetus to an improvised explosive device," Davis said.
Davis said the FBI began investigating Ferdaus, of Ashland, in 2010. In January 2011, an informant cooperating with the FBI secretly recorded Ferdaus as the two men talked about the attacks, prosecutors said.
In a portion of the recording played in court, Ferdaus can be heard talking about "a small drone airplane that can be programmed to hit a target."
Davis said Ferdaus provided two detailed plans to the undercover employees in May and June.
In one, he summarized the plot to attack the Pentagon and the U.S. Capitol, including launch site locations and target locations, flight route descriptions and photographs of the buildings with arrows drawn in to show the points of impact, prosecutors said.
The other was similar, except it also included a "ground assault," the prosecution said. That plan said that when Pentagon employees ran from the building after the explosion, they would be "corralled into certain locations, and others enlisted would gun them down with automatic weapons and grenades," Davis said.
Davis said the undercover employees repeatedly asked Ferdaus if he wanted to continue with his plan.
"Each time that they asked if he was continuing this, he indicated that was all he wanted to do, that was his mission, that's what he was here for," Davis said.
Prior to the plea agreement, Ferdaus' lawyers argued that the FBI ignored signs of mental illness while investigating him.
During cross-examination by Ferdaus' lawyer, Miriam Conrad, back in November, Davis acknowledged that Ferdaus told the undercover employees he was anxious and depressed and was having "intrusive thoughts" in the month before his arrest.
He also acknowledged that the FBI had received during the investigation reports about bizarre behavior by Ferdaus, including a report to Hopkinton police in February that he was standing in the road not moving and appeared to have wet his pants.
Conrad asked Davis whether those reports "gave the FBI concern about the mental health of the target."
"It's a consideration, but it's not a concern," Davis said. "Our concern was for public safety."
Davis added, "Even individuals with mental health issues are a danger and a threat to the public."