Updated

A man accused of plotting to use hand grenades in an attack on holiday shoppers was indicted on charges of attempting to use weapons of mass destruction.

Derrick Shareef, 22, was arrested Dec. 6 by an FBI-led anti-terrorism task force following a sting operation in which an undercover informant secretly tape-recorded his plans. He was indicted on Thursday.

Shareef was arrested when he met an undercover agent to trade a pair of stereo speakers for four hand grenades and a handgun to use at the CherryVale shopping mall in Rockford, Illinois, about 90 miles (145 kilometers) northwest of Chicago, federal prosecutors said.

Shareef is being held in the government's Metropolitan Correctional Center pending a court hearing. No date has been set.

Defense attorney Michael B. Mann, who was appointed to represent Shareef at his initial court appearance in December, was unavailable for comment. A message left on his office voicemail was not immediately returned.

Prosecutors have said they were convinced Shareef had operated alone and there had been no imminent danger to the public.