The FBI has arrested an Oklahoma City man accused of sending more than 700 threatening letters to US officials, Al Jazeera English reported. According to the outlet, he is accused of mailing letters described as hoaxes that contained white powder and warnings about treason. The suspect's name, the charges, the date of the arrest, which officials received the letters, what the powder was and his motive are not known. It is also not known whether he has entered a plea or has legal representation. This is a single-source report that Daily Lebanon has not independently verified.