Federal authorities say an Arlington man is accused of making a threat on Facebook to blow up the D.C. subway system.
A judge ordered a mental evaluation for Awais Younis on Tuesday. He was arrested last week on charges of communicating threats across state lines.
A sworn statement from an FBI agent says Younis told a friend on the social networking site that he could use pipe bombs to kill people on the Metro system and in D.C.'s Georgetown neighborhood. The friend alerted the FBI.
Younis also made threats online against the friend.