LaRose pleaded guilty to related charges earlier this year and awaits sentencing.
Born in Pakistan, Khalid was living with his family in Ellicott City, outside Baltimore, and planning to attend Johns Hopkins University when FBI agents arrested him in July.
Because the alleged crimes occurred while he was a minor, the case was sealed and Khalid was jailed at a juvenile detention center in Berks County. It was unsealed after he agreed to be tried as an adult, his attorneys said.
LaRose and Khalid met in a jihadist chat room more than two years ago, sources have told The Inquirer. He was 15 at the time, but the indictment said he was actively trying to solicit donations and help plan a jihad.
"I have waited for this donation moment for so long," said one of his July 2009 e-mails cited in the indictment, "and I want to make sure that everything is true so that the money reaches the banks for brothers who are true to their intentions and are REAL mujahids not some fbi agents."
His attorneys, Jeffrey Lindy and Alan J. Tauber, portrayed Khalid and his family as hardworking immigrants and said the government had misconstrued his e-mails. They also suggested that the teen's mental or emotional health might become a factor in the case.
"I dispute that he's a terrorist," Lindy said.
Assistant U.S. Attorney Jennifer Arbittier Williams, one of the prosecutors in the case, declined to comment.
U.S. District Judge Petrese B. Tucker scheduled a Nov. 16 status conference for the case and tentatively set trial for Dec. 13.
Last week's indictment named Ali Charaf Damache, an Algerian who used the online nickname "Theblackflag," as the ringleader of the plot. Damache has been detained in Ireland.
The group never succeeded in launching an attack. Officials have said the case illustrates a new type of threat - one in which terrorists enlist white, suburban American women such as LaRose who might draw less scrutiny.
Contact staff writer John P. Martin at 215-854-4774, firstname.lastname@example.org, or @JPMartinInky on Twitter.