Several hours after being taken into custody, Yonathan Melaku has been identified as the suspect arrested in Arlington Cemetery earlier today. He is a Muslim and a Marine Corps reservist. It is also being reported: Authorities said Friday they are investigating the man, whom they did not name, after he was found inside Arlington Cemetery overnight when the cemetery was closed. FBI special agent Brenda Heck said during a press conference Friday that the man, described as in his 20's, had a backpack containing a "non-explosive, unknown material" that she said will require further investigation. "The products in the backpack...