Police blocked off roads around the Pentagon on Friday and searched the surrounding area after arresting a man with a suspicious backpack in nearby Arlington National Cemetery. Police later identified the suspect as 22-year-old Marine Corps reservist Yonathan Melaku. "Melaku was in possession of a backpack that contained unknown materials which initially caused public safety concerns," the FBI said in a statement. "Bomb experts at the scene, however, were able to determine that the items were non-explosive and inert. The materials in the backpack will undergo further testing," the statement read. A bomb squad also searched a nearby vehicle, a red Nissan, but found no explosives. Police closed off several roads around the Pentagon, snarling the morning commute from the northern Virginia suburbs into the US capital. The roads were reopened later in the day.