A law enforcement official is identifying the suspect with suspicious materials in a backpack near the Pentagon as a Virginia man who is originally from Ethiopia.

A law enforcement official who spoke on the condition of anonymity identified the suspect as Yonathan Melaku. The official says Melaku is a naturalized U.S. citizen from Ethiopia. Bomb-sniffing dogs have been sent to his home in Fairfax County, Va.

Melaku was detained early Friday after he was found inside Arlington National Cemetery in the middle of the night. Melaku is in custody, but he has not been charged with anything.

Another official who spoke on the condition of anonymity says the man had what appeared to be an unknown quantity of ammonium nitrate, a chemical compound that can be used in explosives.