Mohammad Hassan Khalid, a legal immigrant from Pakistan who turned 18 this month, allegedly helped recruit women with passports to further the plot of Colleen LaRose of Pennsylvania and others.
The indictment released Thursday also names Ali Charaf Damache, 46, an Algerian who lived in Ireland and married another suspect in the case, Jamie Paulin-Ramirez of Colorado. Paulin-Ramirez pleaded guilty to providing material support to terrorists, the same charge now facing Khalid.
Khalid had been the rare juvenile in federal custody since his July 6 arrest at his family's Ellicott City home. He was an honors student at his public high school who had been offered a full scholarship to Johns Hopkins University this fall. He has been held in Berks County.
"This case demonstrates that we must remain vigilant within our communities to make sure that we bring to justice those terrorists, of any age or background, who seek to do great harm to our citizens," U.S. Attorney Zane Memeger said in a statement.
The teen's lawyer, Jeffrey M. Lindy, did not immediately return a call for comment.
Khalid met LaRose in an online chat room in 2009, when he was 15, according to the indictment and a person close to his family.
He allegedly solicited money for her online and circulated a questionnaire to at least one woman asking about "her beliefs and intentions with regard to jihad," and if she had a European passport, according to the indictments.
In soliciting funds, he pledged to forward money to LaRose, for her to pass on to the jihadists, authorities say.
"I know the sister and by Allah, all money will be transferred to her. The sister will then transfer the money to the brother via a method that I will not disclose," he wrote in July 2009, according to the LaRose indictment.
LaRose, 48, of Pennsburg, had dubbed herself Jihad Jane in a YouTube video that had caught the attention of the FBI by 2009.
She faces a possible life term after pleading guilty to four federal charges, including conspiracy to support terrorists and lying to the FBI. She has not yet been sentenced.