I do wonder how the FBI got onto him? Usually, it is because somone else in the plot got caught or blabbed. that is why true 'lone wolves' like the Unabomber, BTK, etc. run for years without getting caught.
Otherwise, his activities may have been picked up by suspicious persons who reported him - like going into the hardware store and buying pipe, caps, wire, batteries and an alarm clock all at once from the rare clerk who isn't brain dead. Or he tried to solicit others into his plot who balked and told the authorities.
Curiouser and curiouser...
I would put my money on a tip from a concerned gun dealer. Guy probably walked into a gun store and asked, "Which one of these will kill the most infidels?"
"Derrick Shareef, 22, of Rockford, was arrested when he met with an undercover agent in a parking lot to trade a set of stereo speakers for four hand grenades and a handgun.
Federal officials said he planned to set off four hand grenades in garbage cans at the CherryVale shopping mall in Rockford, about 90 miles northwest of Chicago.
He was charged with one count of attempting to damage or destroy a building by fire or explosion and one count of attempting to use a weapon of mass destruction.
Federal officials said that in September, Shareef became acquainted with a witness who was cooperating with the FBI and confided to him that he wanted to commit acts of "violent jihad," as well as other crimes."
And there you are.
I like MediaMole's muse, alot, but seriously, FBI puts most resources on lone wolf types. Lone Wolf targeting even had its own legislation: Section 6001 of the Intelligence Reform and Terrorism Prevention Act of 2004.
The FBI specifically identified the "lone wolf" as the most likely type of Islamist terrorist attacker here in the US.
"Currently, the most likely threat of terrorist attacks from Palestinian groups to the U.S. homeland is from a "lone wolf" scenario." -February 16, 2005 - Excerpt from Testimony of Robert S. Mueller, III, Director, Federal Bureau of Investigation before the Senate Committee on Intelligence of the United States Senate