A Pakistani-born, Maryland honors student, who had hoped to attend Johns Hopkins University, instead pleaded guilty Friday morning in federal district court to conspiring to provide material support to terrorists.

Mohammad Hassan Khalid, 18, was living with his family in Ellicott City, outside Baltimore, when FBI agents arrested him last July and has been in federal custody ever since. Khalid, appearing thin, was wearing a prison jumpsuit. He faces a statutory maximum sentence of 15 years in prison and $250,000 fine when sentenced. No sentencing date has been set.

Khalid, who was indicted in October along with Ali Charafe Damache, is the youngest terrorism suspect charged in the United States.

"This is the saddest case I've ever been involved in," said Khalid's attorney, Jeffrey Lindy.

Lindy said Khalid was only 16 at the time of the offenses, and was a legal resident experimenting with Islamic ideologies at the time.

But federal prosecutors say Khalid went beyond simple experimentation between 2008 and July 2011 when he actively plotted with Colleen R. LaRose, Damache and others to raise money and recruits for a Muslim Holy War.

The Algerian-born Damache, who was allegedly the leader of the group, was living in Ireland and using the online moniker "theblackflag," authorities said. Damache is in custody in Ireland and is being prosecuted there on an unrelated criminal charge.

LaRose, 48, formerly of Pennsburg, Montgomery County, was known by her online moniker, "Jihad Jane." Authorities said Khalid, who is a legal U.S. resident, met LaRose in an online jihadist chat room when he was 15. The indictment said he actively tried to solicit donations and help plan a jihad over the Internet.

In a July 2009 email cited in the indictment, Khalid told LaRose: "I have waited for this 'donation' moment for so long and I want to make sure that everything is true so that the money reaches ... the hands of brothers who are true to their intentions and are REAL mujahids [fighters engaged in violent jihad] not some fbi hungry agents ..."

In addition, LaRose sent Khalid a U.S. passport and other identifying documents belonging to another person, the plea memo said. The memo also said Khalid forwarded those documents to Demache in Europe. But, there was evidence to show Khalid never sent the passport, and instead concealed it so he could personally provide it to the Mujaahideen.

The indictment said LaRose and Jamie Paulin Ramirez traveled to and around Europe to participate in and support violent jihad. Court papers said Ramirez traveled to Ireland in 2009 and married Damache, whom she did not know, as part of the conspiracy.

LaRose and Ramirez pleaded guilty in February and March 2011, respectively, to related offenses and are awaiting sentencing.

LaRose and Ramirez have been in federal custody since their arrests in October 2009 and April 2010, respectively.

Contact Michael Hinkelman at 215-854-2656 or hinkelm@phillynews.com or follow on Twitter @MHinkelman.