By David Schultz
The FBI is investigating whether the students were involved with Islamic extremist groups.
They range in age from 18 to 25 years old and they attended a small mosque in Northern Virginia, where they were involved with a youth group.
Imam Johari Abdul-Malik, who leads a coalition of D.C. area mosques, says the students came from families of modest means who were relying on them for income.
The families apparently noticed their sons were missing several weeks ago. One of the students left behind a so-called "farewell video" containing verses of the Koran and images of U.S. casualties.
The families contacted their mosque's leaders, who eventually led them to the FBI.
Abdul-Malik says the students had not exhibited outward signs of extremism before they went missing.